To keep this response short and sweet, I'll just do a step by step.
First, disconnect both battery cables. Next, put the key in the ignition and turn it to the "accessory on" position (the last position before the engine would turn over). Leave the key in that position for 20-30 minutes. Take the key out and reconnect the battery. This should force the computer to reset itself and reset the light. If it doesn't, you'll like have to get a code reader that can reset lights or take it to a shop and have them do it. Hope this helps.
Works fo me