control a DC motor

Brushless motors require a special feedback circuit. Typically you can use an elcheapo brushless ESC. Theres many many all over the internet. Just find one that has I2C or some other communciation.

Here someones already hacked it with the arduino in these forums:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1226292633