I bought a dvd from gnomon workshop of a concept art tutorial by Mark Goerner. In it he had a file for perspective lines that he placed on his digital work and used as his guides... So I decided to make one myself. I actually made two sets. Two layers, the white layer is separate from the perspective lines.
All you do, after you download it... place whichever perspective lines (or both) into your image. Use the distort feature from the edit menu to make the perspective lines fill your image. (It's best if you are able to have your image mode set to 'full screen mode with menu bar'. Just tape your F key once and you should be able to get there)
Distort the lines to fill the page. Put them anywhere you need, hit ok and they'll be just fine. (NOTE: When you're distorting the lines, they will get pixelated, but they'll become very thin crsip lines when you're done. Trust me.)
Hope these work for you guys and gals... and please... by all means... you know anyone that isn't watching my page that needs these, tell em to come over and download em.