I got GPRS working between the Pearl and the Nokia 770. It wasn't all it was cracked up to be but at least it did work.
I posted the details on another forum, rather than double/triple posting, I'll just give the URL for the informational post: Trouble Pairing my N770 to the T-Mobile Blackberry 8100 Pearl - Page 2 - Internet Tablet Talk Forums
I have this thread and that thread subscribed, so feel free to post in either place. The information in the previous post was key for me, but the nitty-gritty at this point is more in the realm of the 770 than the Pearl, so I'm moving my post to a spot where it may make more sense.