laser guidence for a basic stamp brained valve cover racer
 

I'm trying to make a lserg guidence package for a first robot, and I need some help.

The photoelectric sensor which is hit by the laser is mounted on a disk which has a rotary pisition sensor on it. as the disk rotates, the sensor determines the position of the disk.

When the sensor is hit by the beam, the position of the disk determines how much steering correction is applied (how much the servo that controls the front wheels moves and in what direction)

I'm having trouble finding a suitable rotary position sensor (a single turn pot without a stop would be great, but i can't find one.

any one have ideas for a suitable sensor?

Have you looked at the DigiKey catalog yet? check out their website if you haven't:
http://www.digikey.com

In the print catalog I have, there are all sorts of pots on pages 625-630 that might fit your needs.