Twitterrific
by The Iconfactory
Twitterrific is a fun application that lets you both read and publish posts or “tweets” to the Twitter community website. Easy to use with a ton of features. It has a dark tone to it, where as Twitter itself is very bright. They also make desktop applications. Cool Feature: Send photos right from your phone

Twinkle
by Tapulous Inc.
Discover, connect, and send messages to people nearby. Upload photos and update your Twitter account. Contact old friends and make new ones, all with Twinkle, the location-aware network for the iPhone and iPod Touch.

TwitterFon
by Kazuho Okui
A simple, fast Twitter client for your iPhone.focused on 80% of your task of Twitter such as view friends/replies/messages timeline and send/reply a tweet.

Twittelator
by Big Stone Phone and Stone Design Corp.
Twittelator is yet another Twitter client for the iPhone and iPod Touch. The user interface of this application isn’t as pretty as say, Twitterrific. . .but it does have more functionality.

Twittervision
by PopVox LLC.
Twittervision, a Twitter visualization website built with the Twitter API, using location data from Twittermap (a Twitter/Google Maps Mashup).
Not Free
Tweetsville
by Ed Voas and Tapulous Inc.
$3.99
Timelines let you keep track of what’s going on. Shows up to 200 tweets, Rich text display. *bold* will display as bold, etc., Clickable inline links and @names, Two looks: Balloon and Simple, Displays border for tweets in which you are referenced in Balloon mode and Tap a tweet to view details, send replies, and mark as a favorite.
What next?

