Miranda for Windows

Miranda IM is a multiprotocol instant messaging client for Windows. Miranda IM is very fast and uses very little memory. It does not require installation and can be installed on one floppy disk. Miranda IM's powerful plugin system makes it very flexible. Miranda IM is limited in its functionality, but there are more than 350 plugins that can be downloaded for free.

There are several protocols available:

AIM (AOL Instant Messenger)Gadu-GaduIAX (Inter-Asterisk Exchange)ICQIRC (Internet Relay Chat)JabberMSNNetsendTlenYahooAnd more...