Hi,
I want to use two motors(DC 12v) for to wheels. But i need to control de speed individualy... some one has an example?
Take a look at using a motor shield like this one.
It might be overkill for that, but I like the adafruit motor shield which allows for 4dc motors or two steppers (other options as well) and I figured it out with a little help from users of this forum.
That Sparkfun one looks great if you don't need the other stuff.
Good luck!
-e