The iChat issues I wrote about persist, despite the now-total absence of Virex from my machine. These threads on the Apple discussion board suggests that it is a fairly widespread problem. I’ve read every suggestion, from the mundane (do routine system maintenance and try again) to the exotic (delete some entries in the iChat plist file, make sure your correspondents apply all system updates), to the just plain superstitious (make sure you start iChat before you start any other application).
Me? I think this smells like insufficient testing on Apple’s part, and I’m looking forward to seeing the first post-Tiger iChat update.