Are you sure that your iBook G4 has a DVD drive and not just a CD drive? If you're sure it has a DVD drive, can you be more specific on the problem you're having. Does the DVD mount and just not play, or does it not mount at all, etc.
Yea its a dvd drive!! when i put the dvd in it starts to read it then it throws it back out again.. it does play cds though!
that indicates a problem with the DVD or the drive. Have you tried different DVDs? what DVDs? commercial movies? rips?