ooTunes Radio New! - An iPhone / iPod touch app audio player app that can tweet what song or radio station you're listening to.

QuaseFree - é a primeira aplicação brasileira que permite a atualização do twitter pelo celular. Além disso possibilita o envio de mensagens diretas entre usuários do twitter.

TwitterView - A simple iPhone App that gives the best viewing experience for your twitter updates. Full Landscape support for viewing, posting, direct messageing, and inline web browsing. Excellent for sitting down and Flicking between your tweets with a swipe of your fingers.

Simple Tweet - a simple iPhone application from rhinoapps.com. It allows you to explore, post, remove friends and add friends from your iPhone.

FlyingBird's mobile - a collection of personal productivuty applications for Symbian smartphones, e.g. Money Manager, Car Expense Manager

Twit Tuner - a small and free utility app for the iPhone to browse the current top ten twitter trends.

Book Price Check - a simple way to check book prices via reply and direct message to your mobile device.

twe2.com - is a Free mobile service that allows you to receive your Twitter Alerts via SMS worldwide to any mobile device.

Statuso - An iPhone application which allows you to update toggle on/off posting your status updates to twitter, facebook, friendfeed & yammer

TwitterMobile - A simple to use mobile application that gives the user a portal or gateway into the Twitter world of blogging and instant messaging.

Twittelator Pro - A best of breed twitter client for the iPhone and iPod touch, Twittelator Pro features myriad features sure to satisfy even the most seasoned of tweeters.

Snaptu is a free mobile service that offers you a selection of fun and userful mobile applications, including Twitter, Facebook, Sports and much more. Works on most Java phones.

Twootball iPhone - iPhone application that tracks the scores of the NFL games and the twitter messages about those games. It also functions as client to send out tweets.

Twti2go -  A fast and clean Twitter client for Android powered devices. It has search, photos, URL shortener, etc.

Dabr - The best Mobile Web App for Twitter to date. Described as 'm.twitter on steroids', dabr is ad-free and provisioned for S60, Android, the iPhone and Blackberry... http://dabr.co.uk from your mobile browser

Twitroid is the first full-featured twitter client for Android mobile phones, including search & photo posting.

GPS Twit is an application for the iPhone and Windows Mobile that you can run on your phone to make it easy for your friends to find you. GPS Twit answers the question, "Where are you and what are you doing?"

Quakk is a very small, fully-featured and very attractive Windows Mobile Twitter application.

Tiny Twitter is a free and full featured Twitter mobile client that runs on Windows Mobile Pocket PC and Smartphone devices (a native Windows Mobile client) and Java enabled devices (a J2ME client).

TwitToday is a free Windows Mobile 5+ Pocket PC/Professional Twitter widget for posting Twitter updates from the Today screen

Twobile is a free Windows Mobile 5+ Pocket PC/Professional Twitter client that allows users to use nearly all the features of the desktop web-based version of Twitter!

ceTwit is a free windows mobile 6 native twitter client for windows mobile phones and smart phones

Locify with Twitter service - free. Locify adds gps location to your Twitter update from your phone and more - see public, user and friend timelines, profiles, ... Location Matters! Locify your Twitter.

twitter on Mobio widget FREE DOWNLOAD GetMobio lifestyle portalhas several mobile widgets including twitter on Mobio! Supports 100+ mobile phones [Java + BlackBerry + Windows Mobile phones]. twitter on Mobio widget allows you to update your twitter timeline, view the public timeline, and get updates on your friends timeline all from within a fast and easy to use widget interface. You've got to check this out!

twitter on Mobio + Cricket widget FREE DOWNLOAD The definitive portal for the global Indian has several mobile widgets including twitter on Mobio plus Cricket (IPL, test, ODI), Economic Times, Times of India and more! Supports 100+ mobile phones [Java + BlackBerry + Windows Mobile phones]. twitter on Mobio.in widget is the same as the one in the US GetMobio portal (see above).

Cricket action on twitter Check out the cod at [http://www.theyagar.com/2007/12/02/twitter-action-code/]follow all the indian team's cricket scores from your mobile with plusmo cricket feeds

psychzzz - An easy 1 STEP Twitter Updater for your mobile phone. Supports most major mobile phone browser. XHTML-MP verified and able to support Japanese and Chinese characters as well.

SQIJ -- Sqij is a Windows Mobile application that supports mobile web applets. The Twitter applet makes using Twitter easy, and you can even get alerts of timeline changes and direct messages.

Abiro Jitter supports most features available via the Twitter API with easy access to all features, and works on most mobile phones on the market that at all support Java. It uses your data connection instead of SMS for a lower cost and more functionality, and communicates directly with Twitter for better performance and reliability.

Twitteresce allows Java-Enabled phones (there is a list on the web site) to receive and post tweets. Much more convienent than SMS alerts!

Twitter2Go provides a WAP or xHTML-MP interface that works on Palm, Pocket PC, BlackBerry, and almost any other mobile phone or PDA device. No software to install!

Twitter deBolsillo tested on a Windows Mobile PocketPC. No software to install! In Spanish.

Twapper from 30 Boxes is a WAP browser for Twitter with image support, so you can keep up with Twitter on your mobile without the constant barrage of SMS interruptions. The 30 Boxes blog provides details of Twapper v1.0 and Twapper v2.0b. v2.0b now lets you post Twitter updates.

Twittai is designed for Java phones, which supports most of the twitter functions like Reading Tweets (no 20 tweets limit), Update, Reply, View Archive, View Replies, View Direct Messages, View Friends' Updates and Profiles, Adding Favorites, Delete Tweets, and etc. And Twittai is now compatible with more than 200 mainstream phones and Windows mobile phones.

jibjib is a small and fast open source twitter client for any Java-enabled phones which requires only CLDC 1.0/MIDP 1.0 and CLDC 1.1/MIDP 2.0 in recent versions.

Twitter Answers enables you to Tweet answers and get responses. Like Yahoo Answers for Twitter, powered by Mosio.

Mobile Tweete is a lightweight mobile website. It features user timelines, replies, direct messages, users, favorites. It focuses on being a super-lightweight client.

m.slandr.net is an enhanced mobile site for Twitter, with: replies, direct messaging, users overview, search and geo.

twnkl.org is, like DABR and slandr, a mobile-enhanced front-end to Twitter.  Features replies, messaging, conversation view, searching (with saved searches), blacklisting (remove people you don't want to see from search results etc) and other new features.  Inspired by DABR, written from scratch in Python.  Under active development!

moblf is a platform that enable access to FriendFeed via Twitter. Users can perform the following: Post direct messages on FriendFeed, Get updates from people they are following on FriendFeed, Get updates for a particular user they are interested in.

Twitterpation is an iPhone application that lets you record mixed voice-and-text Tweets.

Hahlo is a mobile application for using Twitter, great for the iPhone too.

HelloTxt is a mobile version of HelloTxt Status Manager.

uTweetMe is a J2ME mobile application for posting Twitter updates.

iTwtr is an open source Twitter client for iPhones. The main thing that sets iTwtr apart from other iPhone Twitter clients is its capacity to download content in the background and save it for future viewing.

Blackbird, a Twitter client for BlackBerry smartphones.

TwitterGPS, a location-aware Twitter client which runs on smartphones which support Global Positioning Satellite (GPS). Users can exchange messages containing location links and then view these as maps - either on the phone or using a PC browser.

PockeTwit A twitter client for Windows Mobile devices. Features a unique UI, GPS integration, Capture photos and send to twitpic, and lots more byRicky Deez.

TwitterText (powered by SmartTouch) TwitterText allows Windows Mobile 6 users a web-like rich interactive Twitter experience through SMS. SmartTouch is a mobile widget-platform that provides an exceptional SMS 2.0 experience for users to enjoy seamless access to branded content and services such as Facebook and Google w/out the need for a data plan!

Twibble mobile is a twitter client for Java enabled devices. It supports all important twitter functions, uploading of photos via twitpic, GPS, and much more!

Twitter Reader is a Web Runtime widget for smartphones built on the S60/Symbian platform (like these from Nokia). Read basic tweet feed, post tweets and @replies. Can also set a custom prefix for your tweets.

Synble is an mobile/web hybrid application for Nokia Symbian/S60 devices. Among other things, Synble can send your @replies and DM's as a text messages to your phone for free. More info...

Map My Tracks shares your outdoor activities in real-time and updates your location on Twitter.

SimplyTweet - An iPhone Twitter client focused on conversations. Supports conversation threading, saved views/groups and multiple accounts.

Touch Poet an Iphone/iPod Touch app which let's you make poetry and publish it to Twitter

twitstar is a Twitter app currently under development for Windows Mobile 6 devices, and could do with some testers!

Coffee Buzz is the Coffee Social on your iPhone - Displays nearby Coffee Locations + All the nearby and everywhere coffee talk from Twitter. Features @replies, Twitter location updates (e.g. 'Starbucks, Boulder County.' not just "iPhone: 51.2342423, 112.01230123"). Automatically composes a 'Having Coffee' tweet using your location and favorite drink.

YiqYaq iPhone is a mobile version of YiqYaq community radio, allowing twitter channels to be listened-to via text-to-speech audio blended with news, music, and other social audio streams.

Gravity is a Symbian S60v3 and S60v5 (touch-screen) client with support for multiple accounts, Identi.ca, TwitPic, and intuitive search features that recognize @replies and #tags in posts, as well as tweet queueing in the event of disconnection from the network.

Twittix is another Symbian S60v3 and S60v5 client with search, auto-update, and support for portrait and landscape mode, and the use of the accelerometer.

Zen Jar is an iPhone app that facilitates anonymous conversation between iPhone users by way of deep, interesting or otherwise meaningful thoughts.  Thoughts posted to Zen Jar are cross posted to Twitter. 

Tweetero an open source client for iPhone/iPod Touch. Supports location, pictures upload, delayed posing (queue).