There are trillions of tutorial like this, I know :-)
They where taking at school during lunch break with a Sony Mavica camera ( floppy disk )!
5 febuary 2001, 12:18:50
Step 1: How to modify a servo motor for continuous rotation ( One motor walker robot )
1 x safety glasses!!
1 x soldering iron
1 x desoldering pump
1 x wire strippers
1 x side cutter
1 x scissors, knife, x-acto, etc
You will need a set of screw driver to remove the four screws on the back of the servo.