Ordered, starting with the best solution:
- Meebo. Offers group chats for ICQ, but this was malfunctional in the current release (2008-04-01). www.meebo.com
- ICQ2Go. The official ICQ web client, but it does not support group chats. See download.icq.com/download/icq2go/ for starting it.
- eBuddy. You may log in to their AIM login form by using your ICQ number. However, you cannot use their AIM conversation and group conference functions that way. The URL is www.ebuddy.com.
- Pidgin (pidgin.im) supports ICQ group chat, but has to be compiled for OS X 10.2. A port for downloading is available for Mac OS X 10.5 Leopard (pidgin.darwinports.com).
- Many more native client alternatives are listed here: http://www.apfeltalk.de/forum/chatprogramme-videochat-voip-t121558.html
- Also look at the list of web clients for instant messaging: http://blogs.tech-recipes.com/tipmonkies/2005/09/20/web-based-im-client-roundup/
- You may look at iChat (de.wikipedia.org/wiki/IChat). But it’s not clear if it supports group chat for ICQ. Perhaps with a software update? See http://docs.info.apple.com/article.html?artnum=106704 for this.
- Fire is no longer developed. See fire.sourceforge.net
- Adium is developed, but does not include group chat for ICQ. See here: http://www.apfeltalk.de/forum/chatprogramme-adium-faq-t129068.html.