Instantbird is a multi-protocol Instant Messaging client. Using it, you can connect to all your different IM accounts.
It uses the Mozilla rendering engine to display IMs, and its own JS protocol implementations as well as Pidgin's libpurple to connect to the different networks (including AIM, Facebook Chat, Gadu-Gadu, Google Talk, ICQ, IRC, Lotus Sametime, MSN, MySpaceIM, Netsoul, Novell Groupwise, Simple, XMPP, Yahoo and Yahoo JAPAN).
Some features are not implemented yet, but most users should find it contains all the needed IM features. We hope you will like it and we look forward to getting your feedback!