There is carbonized version of ICQ for Mac out now at http://www.icq.com/mac/alpha/ although it is a alpha version 2.4 and it is quiet stable but need to figure how to make file transfer work and chat work too. it tells me something about firewalls?
I am thrilled about ICQ for Mac being carbonized and the installer is 100% carbonized so can't install from within OS 9 so must be installed while in OS 10.0 also don't install into Applications itself cuz it require root so install it in your home directory..
I dont use ICQ all that much, or AOL IM for that matter.
I use ICQ more than AIM, to chat with long lost buddies, but I dont really like fire.
I dont know if it's been upgraded since the last time I downloaded it ( december) , but I hate it's interface. In comparison, I prefer the Yahoo! interface