TweetDeck by Twitter

TweetDeck by Twitter screenshots

It helps you build custom Twitter timelines on your Mac.
TweetDeck by Twitter 3.9 : Main Window

Alternative downloads

Echofon for Twitter
1.9
FREE
Echofon is an easy to use, super-fast Twitter app for the iPhone and iPod Touch.
Social for Facebook
2.0.9
This application allows you to check your Facebook account from your desktop.
Twitter Automator Action Pack
1.02
FREE
This action pack extends the power of Automator in Leopard with 10 actions.