I saw a post by Vic Juris on the All About Jazz Forum recommending the Kreutzer Violin Studies as a way of improving your guitar technique. If it’s good enough for Vic Juris, I’m definitely using it. The Study seems like a pretty good resource for some guitar sight reading as well, although the primary purpose seems to be technical. It was adapted for the guitar by Allen Hanlon, and it is now out of print. Scott Abene of Guitarheads.org put the book on his website. I’m definitely going to be using this in my teaching and in my own practice. Guitarists enjoy! If you play another instrument, you may still get some sight reading use out of the free resource.