I've got a 15" Powerbook running 10.4.3, 1.67Ghz, 1.5Gigs of RAM.

I'm having some problems with the sound looping/reverberating for about 5 seconds at a time when I watch DVDs or XviD videos. I believe it also happens if I'm playing mp3s, but it seems much less frequent (if at all, I can't remember for sure). During video watching it seems to happen about once every 20-40 minutes.

It sounds like the audio is caught in about a .5 second loop while the regular sound continues to play, if I pause the video it immediately stops, and when playback is resumed the sound is normal.

What may be the problem? What can be done to fix it?

Yep, checked that, I have it set to drain the battery as fast as possible.

Do system logs say anything about this (or something related to this, CoreAudio problems maybe) ?

You can see the logs with Console application found from Applications -> Utilities.

I don't see anything in the system.log but there were about 5billion other logs that I could view, would you expect one of the logs to be named CoreAudio? Or is that something that would be in the actual text of some log? Any ideas on which ones I should be looking at?

I'd check from system.log (possibly from some others if there's nothing). I meant just lines related to audio. You can also search with Console, just hit apple+F.