Guitar Tablature
I've found that tablature (tabs) is the easiest way to quickly learn chords and songs on the guitar.  Although it has its drawbacks (no timing info) it has the one huge advantage that simple text files can be used.

Note that these files represent interpretations of these songs by the transcriber.  Though I've edited these files I've included the name of the original transcribers if it was available.  I was going to delay posting these until I'd gotten a chance to clean up the notation to make them more consistent.  However, since these files are already hard to find I figured I'd post them just to help anyone who's interested.
 
Porcupine Tree
A Smart Kid How is Your Life Today? Small Fish
Blackest Eyes In Formaldehyde Stars Die
Buying New Soul Jupiter Island The Joke's On You
Disappear Lips of Ashes The Moon Touches Your Shoulder
Drown With Me London The Sound of Muzak
Even Less Nine Cats This is No Rehearsal
Every Home Is Wired Pure Narcotic Trains
Fadeaway Radioactive Toy Waiting Phase I
Feel So Low Rainy Taxi Wake As Gun
Footprints Signify Wedding Nails
Shesmovedon Where Would We Be

 
Genesis
Horizon's