My general rule of thumb is if the miss feels like you are moving the throttle pedal it is fuel related and if it feels more staccato or machine gun like it is ignition related. I am with Dan on spark plugs first. Unless there is an obvious problem I wouldn't just change spark plug wires trying to fix your problem. The original spark plug wires are actually very good and if you don't but the right replacement set you can end up with more problems than when you started. The spark plug ends of the wires should have metal or ceramic shields around them. If they are rubber all the way to the end then they are the wrong wires and should be replaced along with the spark plugs.
The miss going away when you are in neutral doesn't help you as a clue since both the fuel and ignition system are under reduced load.
