Ok, so I have looked around and across the web for a simple Mosfet H-bridge that I can use to power my MKII Tankbot.
So far all I know is aren't they expensive and hard to get to match your specs, so i decided on designing and building one myself.
I had a mobility scooter motor controller which had 20 N-channel IRF3205 MOSFETs which have plenty of power handling for my needs, I have come up with a simple design to incorporate them on to a veroboard after testing on breadboard but the power getting through to the motor is significantly reduced.
I think the problem is that I'm controlling the FETs directly from the arduino.http://www.flickr.com/photos/58848339@N08/5390785968/http://www.flickr.com/photos/58848339@N08/5390785040/http://www.flickr.com/photos/58848339@N08/5390178469/in/photostream/
I have pulldown resistors on the gates of the FETs you cant see them from the photos