I tried to install AIM and MSN for my 8700g, directly from the BlackBerry site onto my device. It installs correctly, but it says that it's not activated for this device.

On another forum, I read that it could be a service book issue. Has anyone else had this problem? Is it possible that AIM and MSN simply won't work on the 8700g?

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+).

I use Nimbuzz that combines all of the messengers under the sun. Go check it out. You can download the alx files from their website.