iPhone + HDMI

I finally got to use my "Apple Digital AV Adapter" with my new TV. It works great, I can watch YouTube on my TV with just my iPhone, but not many other apps work.

iPhone 4

• Only apps which are specifically written with HDMI out work. In particular: Video and YouTube
• Photos, Safari and Angry Birds don't work.
• Music app plays through the HDMI cable, so you don't need another audio cable.

iPad (and I think iPhone 4S)

• Apps written specifically with HDMI will do whatever they're programmed to do. E.g. YouTube will display controls on the iPad and video on the TV.
• Apps written without HDMI e.g. Notes, Safari, will mirror their display on the TV