I just built a prototype analogue servo, it uses a vehicle wiper motor, a pot for feedback, an l298 for power control and serial data in for positional commands on a pic16f88.
The software implements P and I, reasonably crude but it seems to be very effective and quite powerfull for something that cost next to nothing.
I searched the site and didnt find a great deal on servo's, except for controlling rc servo's via software, I was just wondering if anyone else has done this and what kind of results they got, I'm thinking maybe switch to a quadrature encoder for feedback, noise is an issue.