I had to call into T-Mobile technical support to find out that T-Mobile does not provide Service Books for the 8700 AIM application. They state that it is not compatible. I opted to get IM+ since I run a small Jabber/XMPP server at work, and I like having a single unified client for my needs.

I've seen a few posts around referencing loading of SB's from other carriers and or models of the BB, but I am not certain as/to how well this will work, and from the research I have done it seems very problematic.

I also plan to try a few other 3rd-party applications before I purchase (on my 7-day trial of IM+).