Differential drive with 2 brushless motors and joystick

I would like to connect a joystick (2 pots) and control 2 brushless motors for differential drive, i.e. like tank treads.

How do I do this? Any examples and detailed explanations are appreciated!

What sort of brushless motors?

See this thread - which is essentially what you need:

http://forum.arduino.cc/index.php?topic=172581.0

Another differential joystick discussion.

http://forum.arduino.cc/index.php/topic,157967.0.html