Many posts in the past have asked how to handle GTD process with Blackberrys (BB). And some cumberson 'hacks' have been tried.
Gary Slinger has posted in his blog an excellent methodology compatible with Outlook and the GTD add-in (would work without the add-in as well).
A key is to think of the BB mostly as a collection tool and if you are willing to take some time every morning to integrate some of the things done in the BB to Outlook, you can also use the BB for processing.
Netcentrics claims to be working with RIM for quite some time for a compatible add-in but no further information has been posted. Maybe Davidco sees a commercial opportunity with all those BBs around and can expedite this product.
Take a look