TweetStation

Audio

Chicken noises
Sampled chicken noises are played back on refresh to ensure that you do not take Twitter too seriously
Music Playback
Music playback during message composition will encourage you to write the best possible tweet you can, to create witty and insightful remarks instead of yet another "me too" comment.

Cute UI elements

Pull to Refresh
This feature originates from Tweetie (now Twitter for iPhone) and we brought this feature.
Local search
You can now search for text on your local tweet display without having to perform a server search

The Basics

Common tasks on the main page
Home, mentions, favorites and direct messages are all accessible from the main page without having to drill down. Keeping favorites on the main page was important to ensure that you use the favorite features effectively
Easy Access to Information
When you tap on a tweet, you can immediately glance the information from the poster, check the poster's timeline, and follow the discussion without having to navigate to user-specific pages
Searches
Searches for users, trending topics, your personal topics and your twitter saved searches are supported as well as scanning for nearby tweets.

OpenSource

The source code is open source, and anyone can use it to create new iPhone applications based on this model, reuse any of the code in it or enhance Tweetstation.

The source code is available at GitHub