Hmmm. After searching some more, it seems to make 5 amp controller isn't so easy. I've always been used to the Arduino motor driver tutorial that uses the L293. It's a 5 minute setup.
http://itp.nyu.edu/physcomp/Labs/DCMotorControl
(This is a great tutorial!)
Is there not just a beefier L293 type of chip that would let me control 5 amps instead of 1?