"I assume the other apps dipped into the H.264 stream that the BBC supply for iOS devices. Everyone else is now locked out of that since certain client certificates shipped only with those devices are required."
Actually no. The Beeb got rid of the app from the Market, but I guess the API was already too well established, and locking it to devices would get the Beeb in trouble very quickly. BeebPlayer still works! Assuming you used ASTRO or similar to back up the *.apk... ;-)