I recommend Gaim or Chatzilla because they are easy to use, cross-platform and open source. Other popular ones include X-Chat (Unix/Linux), AdiumX (Mac) and Fire (Mac).
Why choose Gaim?
Gaim is slick, and it supports many IM protocols like AIM, ICQ, MSN and
Jabber. Learn how to use Gaim and you can use it for everything.
Why choose Chatzilla?
Chatzilla is a plugin for Mozilla and Firefox. It's a one-click install
(click the link below). Chatzilla lets you have your IRC client right on
your browser.
Instructions for Gaim | Instructions for Chatzilla |
Instructions for Gaim | Instructions for Chatzilla |