SonexBuilders.net

Check out the ez-autopilot at trioavionics. Basic functionality that won't break the bank. Check out the user manual for complete functionality. Will talk to gps unit, fly headings, waypoints. Limited altitude function but for a brand new system at around $2k, it's not a bad deal at all.

EDIT: Actually, the altitude control is a separate add-on for about another 2k. The "Pro" level version is somewhere around 6k and is GA certified.