Trillian is a computer program that allows users to access various chat and instant messaging services using a single interface. It also works as an IRC client. Trillian also supports the features found on the various chat services, including file transfer, video chat, group conferencing and much more. The paid version of Trillian called Trillian Pro supports even more chat services, including Jabber and Rendezvous.
IRC on Trillian vs Mibbit:
Trillian operates in its own windows, unlike Mibbit, which is an IRC chat program that operates inside of a browser window. Trillian has its own icon in the Windows task bar. When a Trillian user joins rooms within an IRC server, a window for all the rooms opens up, and each room has a tab. Trillian allows the user to separate these tabs into separate windows, if desired, so that the user can see at a glance which window has a message in it. Trillian has a much more stable connection to an IRC server than Mibbit has, as well.
Supported Software
Here is a list of all the IM networks supported by Trillian.
Walkthrough of Trillian's Features
This user shows the Trillian screen and tells all about the different features of Trillian. He says he likes Trillian better than any other chat program he has tried including AIM and Yahoo. The version of Trillian shown on this video is an older one. The newer versions look quite different, but function similarly.