For some silly reason, AT&T is not supporting BlackBerry Bridge—the lifeline of the BlackBerry PlayBook. Remember, in order for the PlayBook to access email, contacts, and calendars, it needs to be "bridged" to a BlackBerry via the BlackBerry Bridge app. Without access to BlackBerry Bridge, AT&T is effectively neutering the tablet for AT&T BlackBerry users.
We're assuming AT&T is not supporting BlackBerry Bridge on AT&T BlackBerrys because they're considering the service as tethering, and tethering costs more. If that's AT&T's prerogative, fine. Well, stupid, but fine. RIM needs to wise up and add native apps for those services anyway, they shouldn't be risking the experience of the PlayBook in the hands of the carriers.
But who cares if AT&T or RIM is more at fault. If you're an AT&T BlackBerry user who wants to use the PlayBook to its fullest, you need BlackBerry Bridge! Luckily, CrackBerry has found a loophole: You can download BlackBerry Bridge for AT&T right here. [CrackBerry]
Update: Here's AT&T's statement:
AT&T is working with RIM to make the BlackBerry Bridge app available for AT&T customers. We have just received the app for testing and before it's made available to AT&T customers we want to ensure it delivers a quality experience for our customers