I’ve created a sample project on github that demonstrates how to use a webcam in Molehill. It’s not really any different than using a static texture, except for these lines:
snapshot.draw(video, snapshotTransform); texture.uploadFromBitmapData(snapshot);
The performance is very impressive, and you can see from the code, it was simple to do. Hooray for Molehill.
Edit: Updated to work in Flash Player 11 beta 2.