Miranda IM is a multi-protocol instant messenger client for Windows. Miranda IM uses very little memory and is extremely fast. It requires no installation and can be fitted on a single floppy disc. Its powerful plugin system makes Miranda IM very flexible. Only the most basic features are built in, but there are currently more than 350 free plugins available for download that allows users to extend the functionality of Miranda IM.

Available Protocols are:

AIM (AOL Instant Messenger)
Gadu-Gadu
IAX (Inter-Asterisk Exchange)
ICQ
IRC (Internet Relay Chat)
Jabber
MSN
Netsend
Tlen
Yahoo..