Is my computer slowly breaking or just needing a cleaning?

Ive got a 12 inch Powerbook G4 that I bought 3 years ago in August. Since Ive had it, and especially for the past year it has been very loud, and also very hot. I realize my machine is getting older, but I would like to hold off buying a new one until the new Macbooks are released. Ive heard of powerbooks behaving this way, but would taking it to the apple store, paying to get it cleaned do anything to prolong the life of it?