Local

• GeoFollow - Local Twitter Search - Geo (location based) twitter directory. (Add youself on twitter by sending @geofollow YOUR CITY, YOUR STATE YOUR ZIP #tag1 #tag2 #tag3. EG: @geofollow Walnut Creek, CA 94596 #directory #geek #people. Largest location based Twitter Directory on the net.
• LocaFollow - A Tool For Searching and Following Local Twitterers - A Twitter search engine that enables you to locate and follow Twitter users by searching in their Bio and Location fields.
• iAte - Automatically tracks tweets about restaurants. Find out what twitter users are saying about restaurants near you. What are they eating? What local restaurants are popular? Share what you ate.
• Localtweeps - Localtweeps was created to help localize the Twittersphere. Get found and find Tweeps in your city and zipcode.
• GoTwitr- GoTwitr combines all the best features from automation apps into one simple yet powerful site.  GoTwitr offers a whole new concept in building a smart Twitter community.  When you give this great service to your followers, they will promote you to their followers.  Their followers will also promote you too, at every generation, making a smart viral growth of REAL users. Never blindly follow or purge again! Gotwitr lets you preview users before you take any action. Local, mimic, and keyword follows are easy to use and powerful too.  Define your community into groups, and bulk message with personalized messages.  Other automation features too numerous to mention here.
• Map Your Friends - A script from Twittas? that locates your last 100 friends on the map
• StreetMavens - Real time social media and information by City and category. Post photos to Twitter, easy to Reply and RT, view recent @replies. Also features local maps and radio. Full mobile site (including photo uploads) and API available.
• ChirpCity is Twitter by city. Local search, latest tweets about and from your city and a top users list.
• Windy Citizen Twitter Tracker is a Twitter buzz tracker for Illinois' special election to replace Rahm Emmanuel in the United States' Congress. Graphs their Twitter mentions over the last two weeks, pulls quotes from linked articles and lets you sift through messages mentioning all of them. It's the first local, political Twitter mashup.
• Twitter Users by Location. You can find list of Twitter User organized by Country.
• It's On - Easy event-casting using Twitter. Add an event by simply sending a message to @eventin city: event info. Search events in your city and "unbored" yourself.
• Tweeple of India - A listing of tweeple from India
• Breaking San Francisco News - One of many Breaking News city sites that aggregate the best Twitter feeds in a city by category: news, events, shopping, food, etc. Also Los Angeles, NYC, Boston, London, Toronto. See one of the sites for a list of all cities.
• Happn.in - Happn.in shows you what people are Twittering about in your city.
• Tupalo.com - Find, rate, review and Tweet about the best local businesses in your neighborhood or around the World.
• EarthTwit - website which allows users to update and share their current location or other places. Integrated with geShout.
• enote.in - A twitter client + application that lets you post updates in 6 languages
• OnlineGlobeGrid - OnlineGlobeGrid - Find & Talk to users within your city, zipcode, within radius of a mile of your location, even people on your street or even your nextdoor neighbors.Sign in & mark your location. Get more friends, Get more Business, Get more Information in your local area or anywhere on the globe. Real time geo social networking powered by Twitter
• Twibez Real-time tweets on Google maps. Twibez can be useful for everyone who is interested to see where in the world twitter users are discussing top trends in real-time. Basically, Twibez is a fun tool to get a geographical impression of what the world is talking about right now!