MrJones:
One question that comes to mind right away about you code. Wouldn't i have to increment in steps of 1 always since if i increment in steps 5 and my target is not an interval of five it will over shoot and oscillate the speed, never getting to target??
That's possible,. I just used 5 for illustration.
I felt I needed to leave something for you to get your teeth into 
...R