Pidgin is a chat program which lets you log into accounts on multiple chat
networks simultaneously. This means that you can be chatting with friends
on XMPP and sitting in an IRC channel at the same time.

Pidgin is compatible with the following chat networks out of the box:
Jabber/XMPP, Bonjour, Gadu-Gadu, IRC, Novell GroupWise Messenger, Lotus
Sametime, SILC, SIMPLE, and Zephyr. It can support many more with plugins.