Oil pressure switch. Replace it, it costs about 25 bucks at autozone. I had the same problem with another car. If thats not it, then make sure your not loosing oil pressure. Next obvious steps, Change Oil, Oil Filter, make sure your not leaking oil, and then check and or replace your oil pump. Theres only so many things that could make an oil light come on. A. Loosing Pressure, B. Low Oil. Thats about it.