RIM could have developed the PlayBook to be able to if it had chosen to. Apple created FaceTime as an open standard for video chat, and third-parties like RIM are welcome to use it.
The Video Chat app seems to have some nice features, and PlayBook owners will surely welcome a chance to put the front-facing camera to some productive use. But, I think RIM missed an opportunity by not embracing FaceTime and letting the PlayBook connect with the millions of iPhones, iPad 2s, and Macs out there.