The fan in my notebook has been making a ton of noise lately - actually it sounds like a jet taking off. It does it only on start-up, but than after a few minutes, it stops. It kind of sounds like it might be brushing against plastic or metal. Has anyone ever removed or adjusted a notebook fan, and should I attempt it?

I wouldn't attempt to adjust it. When fans start to get loud all of a sudden (when they've always been quite before), that's usually a sign of the bearings dying a slow and painful death. You could take a can of air to it (while it's running) and blow all the dust/debris out to ensure that it's not just getting bogged down by dust or things of that sort. The fans themselves are fairly inexpensive, so you'd be better of to replace it if you think it's faulty.