Do you mean the "Check Engine" light or the "Oil Pressure" light? Because if it's the oil pressure light and it's still on the engine is probably in sad shape.

You never drain all of the oil out of an engine with an oil change so there was some still in there. They DO show running an engine without any oil on those after-midnight infomercials so if you use synthetic oil it's possible that the engine wasn't destroyed.

Also, if it was just idling there was no LOAD on the engine. (Let's look at the factors optimistically!)

I'd check the oil pressure with a gauge. If the engine still builds normal oil pressure I'd just drive it. Maybe not across the entire country but what can you lose at this point?

-Sam