Here's a start on locating them: http://docs.info.apple.com/article.html?...

I'm not finding a guide or parts listed anywhere but take a look at this guide through step 8: PowerBook G4 Titanium DVI Logic Board Replacement

At the bottom of the logic board next to the case you'll see two white connectors to the logic board. I believe those are to the speakers which should be able to just lift straight out. If you want, I'll see if I have one of these machines for parts and see if I can pull the speakers with ease.