leaking oil from top or engine

This sounds like a serious oil leak problem, if the oil is in fact engine oil. It could be that the oil sender for the light/guage is leaking ( not an uncommon problem ) which would make the light go on with out there being any catastophic damage YET! I would tow your vehicle to a really good shop and have this problem completely resolved because you could ruin your engine (in a heartbeat) with a loss of oil and/or oil pressure.