GoPro have announced that they are working on adding a live output function (perfect for FPV) in a future firmware release. Although the current GoPro Hero can be hacked to output live AV, it would be much nicer to see the feature added in firmware.

Currently the HD HERO camera is set up to only allow playback of previously recorded files when connected. We are however working on a free downloadable firmware update, that will allow the camera to provide for a live video output when connected via the AV cables.