Although I have a BB (7510); I don't use it for GTD. A bit to primitive for my taste! However, after looking at Steve's blog, I'm a little more interested.
For now, I'm using my iPaq 3870, synced to Outlook 2003 which is setup using David's "outlook pdf" instructions. Works fantastically for me with no add-on programs needed. (Only problems are that entering a task on the iPaq is cumbersome; and when you mark a task as "private" in Outlook, you can't see it on the iPaq!)
Problem is, I now carry an iPaq, a BB (both belong to my employer), *and* a personal cell phone...thus necessitating that I carry a "man bag" around everwhere I go. If I could run GTD from my BB, then I might be able to ditch the bag, and carry my life on my belt...like the good old days!
So I'll be watching this thread, and Steve's blog, for tips.