DisplayOut

Mirrors screen on connected monitor, projector or television

Detects orientation and connectivity

Supports game and video content

Customizable zoom & aspect ratio

iPhone 4, iPad, iPad 2 and
iPod touch fourth generation:

Official HDMI adapter + iOS4.3 (best)
Official VGA cable (better)
Official component cable (good)
Official composite cable (okay)

iPhone 3G S, iPhone 3G, iPhone, iPod touch 2nd/3rd generation:

Official component cable (better)
Official composite cable (okay)