Training a paint arm robot

Several years ago I saw a program where a robot paint arm was
trained manually by moving the paint arm. The arm was placed in lean
mode and then a person would paint the object by moving the arm.
Once the training was complete the robot could duplicate the spray
pattern. Does anyone know an easy and affordable way to implement
this? I know that Galil Montion Control board's have a
learn/training mode; however. I would have to spend over $6,000 on
controller boards, not to mention the encoders and motors.

My thinking is a PC based system that would record the timing and
signals on the various encoders for the lean mode. I would think
this would be a relatively easy program to write, and there should
be some shareware or low cost software out there. Does anyone have
any ideas?

Thanks
Bill