There's no BBM app within the BlackBerry Bridge yet... but it should be there within a few weeks!
When I was working on my BlackBerry PlayBook Review, the version of BlackBerry Bridge I was testing lacked BlackBerry Messenger. RIM said they were working hard to make it available for launch, but it looks like it didn't make it into the build that went gold certified for launch. I reached out to RIM for a quick update, and here's the scoop:
...a software update for BBM functionality is expected to be available within a few weeks, and customers will be able to download the software update over-the-air.
So there you have it. It's coming soon. Hopefully we'll see Video Chat hit around the same time, so we can start putting that front-facing camera to use too!