I got this again last night at a mates - the car WAS parked on a hill for a few hours - facing upwards if it makes any difference, and wasn't a steep hill :S
Went to drive home and got the OIL------ and SERV on the dash. Pulled in at a garage halfway home to find my oil on the Min marker
Anything else I should check apart from the dipstick before I top-up?
Why bring Jason_E into this??
You should check your oil when the engine has been off and on level ground for at least 15 minutes, which gives it time to flow back down. If you drive it, and pull into a garage and check it straight away, of course you're going to get a low reading, as most of the oil is spread about the engine.
Parking facing up hill sometimes does bring a warning up, as the sensor is at the front of the engine.