BeeJive IM [$9.99 - iTunes link] for iPhone and iPod touch has just gone 3.1 and now includes group chats (on IM services that support the feature, AIM, Yahoo!, GTalk, MSN), and meta chats (allows you to merge contacts with multiple IM services into a consolidated stream -- So Bob's AIM and Bob's Gtalk just show up under Bob).

We've been testing out the beta for a while but now that 3.1 is live, we'll be able to test it much more extensively and provide updated results as soon as we have them. Meanwhile, if you get a gaggle of chatters all grouped up together, give it a while and let us know how it works for you!