Telenav should work with the iPhone plan as long as the TCP APN settings are programmed into the BB. I am not certain about the AIM client, but Jive Talk is an excellent multi client IM program that will work with it also. There are a couple email programs floating around for pop and imap services however they seem to me to be a bit rough around the edges. The gmail application is really nice if you use gmail and I also recommend Flurry Mail is a good basic application/service that works with multiple mail accounts (an aggrigator of sorts). I used flurry on my Blackberry before my provider had BB services, it can be found at flurry.

Hope this helps.

BTW I have an 8310, the GPS works well and its a great overall device.

Added: You might be a bit hard pressed to find the Desktop Installation files for Telenav, however I did use it when I was using a standard PDA plan and don't recall when I found them. If you cannot find them then find someone with an ATT BIS plan and have them place their sim into your device and do a quick OTA download of the applications you want installed. Once you reinsert your SIM back into it the blackberry browser will disappear again but the apps you installed should still be there. Do not open and run them while the other persons sim is in the device, you want the applications to initialize internet connections via your data plan not BIS.

Good Luck and Happy Berrying!