Apple offers the Digital AV Adapter, which connects to an external TV or projector with an HDMI cable. Video mirroring is integrated into the iPad 2, sending whatever appears on the screen to the external device in 1080p HD video. A separate port on the same cable connects to a 30-pin Apple connector, allowing sync or charging while connected to HDMI. The Digital AV Adapter will be available for $39 from Apple.
Apple Digital AV Adapter