Double speed on video, normal on audio! What do I do?

Hi,
I've downloaded a bunch of Futurama episodes and all of them play the video at double framrate (In Videoinfo, framerate's about 60). The audio will therefore not be in synch with the video at all! When changing the playbackrate to 1/2, the video plays at the correct rate, but now the audio is of course very low pitched (or whats it's called), so everybody taaalllkks liiikeee thhiiisss.... well you know(:-)).

Am I missing some filter or is there some setting which can fix this?! I've tried to search for it, but with no luck.... I've played a lot of movies, but never with this problem, so please help me guys!

Thanks.