I have something called OZ instant messenger. It has AIM Yahoo and MSN. You can only use one at a time tho. Other than that and I think it drains the battery it works. I just usually stick with the trusty BBM!! Lol.Also, I remember downloading it for free from my provider. AT&T but you'll have to see what your provider offers.
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Yeah BBM is good, if you have friends on there. I use MSN and Yahoo at the same time with no problems. Just give it a try. If you don't like it, delete it and try another messenger.........
Beejive messenger is another good alternative. Supports AIM, iChat, MobileMe, MSN/Windows Live, Yahoo!, MySpace, GoogleTalk, SameTime, ICQ, and Jabber.