Since I got the FEZ Cerbot I have been wanting to implement a line follower, but it has just never happened. Well this evening I decided I needed a break and here are the results from my first attempt.
I will post the code once I have played a bit more, I would like to see if I can improve the navigation of sharp corners.
Right now the logic is very simple, if the reflection on one side drops below a threshold (50%) I speed-up the opposite motor and slightly reduce the speed of the other. The motor speeds do not immediately return to the default speed once both sensor are on track, they adjust back to the default speed over time.