If you want to buy professional guitar TAB sheet music online, you really have two choices: Hal Leonard’s GuitarInstructor.com and MusicNotes.com that offers a lot of Alfred Publishing songs. Between those two services, you should be able to find almost any song you want to play. Here’s the PR blurp for MusicNotes.com:
Musicnotes, Inc. offers an online catalog of 100,000 digital sheet music titles, built on the strength of content agreements with Alfred Publishing, EMI Music Publishing, Faber Music Ltd, Sony/ATV Publishing, Universal Music Publishing Group, Disney Music Publishing, Cherry Lane Music Company, Peermusic, Word Music, EMI Christian, Bug Music and many others.
I usually buy my songs online from Hal Leonard, but now that I’m dipping a bit more into guitar Jazz, I was desperate to find “Take Five” — scored for the guitar — written by Paul Desmond and made popular by the Dave Brubeck Quartet. I found just what I wanted, and more, on MusicNotes.com: