I wall add an anicdote (sp?) once on Wendys bike after washing it she had gotten water under the boot on the sending unit causing her oil light to stay on. I paniced thinking the oil pump was bad. Prompted me to make our oil pressure gauges so I could see what the actual pressure was. Could be something along those lines. Water under the boot or a bad sending unit or another simple cause. Cowboy is also correct in that you will not get a correct reading if you check your oil right after running the bike. There should be a small part of the sight glass with no oil at the top if the level is correct at it's max. If the entire glass is covered chances are that qt. you put in over filled it and needs to come out.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!