Lot of people mistake the bluish white smoke of oil for just white, pure white, from coolant.
Not unusual for a small amount of fluid (water) to run out of the exhaust at times. It may be black from all the carbon crap that builds up in there (especially if your car burns oil, or used to in the past)
Good advice not to drive it more than absolutely necessary if you think it's the head gasket, but if it was in fact the headgasket, and it's been smoking like that for a while, you should have either noticed a change in your coolant level or the coolant could be very dark from oil entering into the coolant. Possibly both.
Last edited by A-series; 11-08-2007 at 09:27 PM.