If you post on twitter but you don't like having to load a browser, type in twitter.com, log in.. and all that jazz, then twirl is for you. I've tried tweetdeck, twibble, amongst others... and so far I have to say I love this app the best.
twhirl is a social software desktop client, based on the Adobe AIR platform.
Some of twhirl’s features:
* runs on both Windows (2000/XP/Vista) and Mac OSX
* connects to multiple Twitter, laconi.ca, Friendfeed and Seesmic accounts
* displays notifications for new messages
* shorten long URLs (using digg.com, bit.ly, snurl, twurl or is.gd)
* cross-post your updates to Jaiku and many other sites like Facebook,
MySpace, LinkedIn and more via Ping.fm
* post images to TwitPic
* search tweets using Twitter Search and TweetScan, and follow topics in
near-real time with saved searches
* automatically find tweets mentioning your @username
* record a video on Seesmic, and share it on twitter immediately
* get your seesmic updates in real-time using XMPP
* English spell checking
Download Here