Trillian Astra

Trillian lets you connect to multiple IM and social networks at the same time, managing contacts and real time status feeds efficiently. This application comes with a very nice interface, has 400+ features, support popular IMs and social networks like Yahoo, MSN, ICQ, AIM, GoogleTalk, Facebook, Twitter, and many mores. Until now, it's currently available only for Windows OS and Web based version. MacOS and the iPhone one is still on testing.

You can download this nice application from HERE for free.

Some screenshots :