coolant in oil of 2008 Pontiac G-6

If you haven't started the car, just drain the oil - no flush needed ... the coolant should come out first, considering the oil is lighter. Basically you want to give your car an oil change. If it's close anyway, not a big deal. There may be a little bit of coolant which is left over (residual trace amounts) after you drain the oil. Don't worry about this too much, as it should evaporate after a good long drive. Any other residuals should come out after subsequent oil changes. There really shouldn't be much in there after the first oil change, though, so not much to worry about.