Movie-making software suggestions pl?

[NuttyNoelAgain]

My 14 year old DS is physically disabled, so isn't looking for a skateboard this Xmas!
However, he's really into making short movies, accompanied by music, and putting them onto disc or uploading them onto YouTube. He has done some lovely ones on Windows Movie Maker and I think he could really get into this (maybe even find himself a career?) Unfortunately he's saddled with a non-techy Ma.
Can anyone suggest any software/gizmos/books etc that might enhance this hobby of his? He especially seems to have trouble sometimes laying the music tracks of his choice onto the video (perhaps licensing problems?) so anything I could get him to make this more straightforward?
Any suggestions gratefully received.