If you play guitar you might be happy to learn there’s new tabulature at the “OLGA” database. This was closed a while ago for copyright infringement (not unlike the current furor over Napster). Apparently now they’re getting around that by simply linking to tab on other servers; it’ll be tough for the Harry Fox agency to sue all those folks.
Personally this tab doesn’t keep me from buying sheet music – the quality isn’t that good (kind of like substituting streaming RealAudio for CD-quality sound, yuck).