If the scratches are in the clearcoat only, try Meguiar's Scratch-X. If they are fairly significant, it'll take a lot of elbow grease and you'll likely only be able to reduce their apearance, not completely eliminate them. I have a Griots Garage catalog that has a nice guide in it to various scratch types and what can be done about them, but I can't find it on their website. Meguire's is good stuff, though, and I usually follow it up with Kit Scratch Out, an even finer, very cheap and easily obtainable compound that really makes the paint like glass.