I'm far from up to speed on this, but from memory and quick search, no can do AIM on AT&T (unless I've missed something new). See for example cannot download aim
. There are numerous threads.
Regarding yahoo messenger, see the following example links. There are a number of threads. Bottom line, you'll have to add service books yourself because AT&T does not provision them. I can't say these are the best threads, but should get you started. BB Yahoo Messenger 2.0 http://www.blackberryforums.com/blac...tml#post334068