EDIT: I had a post earlier that seems to have been claimed by the anti spam mod approval thing which said something about finding the mosfet data sheet **broken link removed** If i'm reading that datasheet right (and I'm probably not) It looks like to turn the transistor to the ON state, it requires 2-4v across the gate and the source, if this is correct, would that mean that the source is our ground and the gate is our positive voltage out of the arduino, and the drain is the ground for the primary winding on the coil?
Obviously I'd need some sort of protection circuit to protect the arduino, any ideas on how?