Meebo
 

http://www.androidfreeware.org/image...hots/Meebo.png

Description
Meebo for Android is a multi-protocol instant messenger client. It supports AIM, Yahoo!, MSN, Google Talk, ICQ and Jabber IM networks.

The Meebo client for Android runs in the background and displays new notifications in the system tray.

Features:

No SMS charges!
Application runs in the background
Displays notifications in phone's system tray
According to the developers "this is just the first version. It doesnt have every feature that you would look for in a full blown desktop IM application...