Not sure where this goes so...this is as good as any...

Some Internet Explorer 7 testers who loaded the Beta 1 bits onto their systems have found a nasty surprise BetaNews has learned: their instant messaging software crashes.

Trillian, a popular multi-network IM client, Gaim and IM2 all spit out error messages when loaded alongside IE7, and the only fix is to uninstall Microsoft's new browser.
http://www.betanews.com/article/IE7_...pps/1122670369
BetaNews | IE7 Beta Breaks Instant Messaging Apps