Mac OS X: Trillian, the slick-looking multi-protocol IM client has launched an early alpha for Mac OS X. It's not close to feature-complete, but it does look like Trillian.
Early reports peg the Mac alpha of Trillian as very rough, and not on the same level as the well-known Windows client. Some preferences are missing, Growl support isn't there, and, as Download Squad notes, the chat alert sounds are annoying and hard to turn off. That said, the client has a smooth look to it, and, while Adium is the well-tested standard for multi-protocol chat on Macs, if you're familiar with Trillian on Windows, you'll probably enjoy the Cocoa-ed version seen here.
Trillian Alpha is a free download for Mac systems only. Give it a shot and tell us what you think of Trillian's new platform in the comments.
Help Shape Trillian for Mac – Alpha Build Now Available! [Cerulean Studios via Download Squad]