i i am in same situation, i have the 40GB version MG575AH , just bougght today.
the sales showed me by plugging in USB to the computer and imovie found the cam. when i got home, using also imovie o8 i set everything up but nothing..........then i tried using thye craddle and firewire cable (cable not supplied) and once i hit play on the cam imovie asked me if i want to import the movie. i hit yes and then the whole movie plays and imports.
so somehow it works, i just dont understand why it has to play the whole movie on the camera (and the lcd screen)
anyway editing and saving with imovie and idvd was a blast, but imovie and idvd took about 30 minutes each to render and burn the disc with only about 25 minutes of video.