I was able to reset mine by disconnecting the battery for 5 minutes or so. However, I'd have a car parts place check your engine code (typically for free) before you do that.
If the problem still exists the light will come back on possibly pretty quickly. If you want to reset because of an emissions check you need to have driven the car for a period of time after resetting or they will flunk you for not having any data in the OBC storage. Or at least that's what they told me!