True, you don't need to learn to read music, but it opens up a lot of sources of new material (i.e., song books, sheet music, etc.), and if you can learn to read for the guitar as well, the sky's the limit. You'll understand a lot more about the layout of the fingerboard, and that can open up possibilities that you probably wouldn't figure out otherwise.

About the easiest way to learn to read music, since you play the guitar, is to pick up a beginning guitar technique book that uses written music, and just play through the exercises. The ones I'm most familiar with are for classic guitar (manuals by Aaron Shearer, Christopher Parkening, Frederick Noad, and others), but this doesn't mean you would need to know classic guitar technique, and although the manuals assume a nylon-string classic guitar, there's no reason that the stuff can't be played on a steel string guitar. Maybe a good idea to drop into a music store and ask for a beginning guitar book that can teach you to read music. .

I know there are a lot of musicians out there who don't read music, but there are a whole lot who do. Reading music is a basic tool for musicians. Why handicap yourself?

By the way, the keys you can play in (C, G, D, A, and E – you need Am, Em, and Dm also) are about the only convenient keys on the guitar. All the others get you immediately involved in a lot of bar chords, and since they are rough keys to play in, most classic guitarists don't like them much. So classic guitar composers avoid them, lest their stuff just doesn't get played! For song accompaniment purposes, keys other than those mentioned above are capo territory.

Don Firth