95 Escort rattling white smoke from engine

1995 Ford Escort Lx hatchback, 168,000.My car started making a rattling kind of noise a few days ago,this only happens when the car is in gear and when you press the gas.Well yeaterday I was bringing a friend home and the rattling type noise got louder and then when I parked the car we saw white smoke coming from under the front of the hood in the center and smeeled oil.The noise sounds like it is coming from under the hood,but it has to be driving for a bit before you can hear it.I did however start the car a couple hours later and it didn't smoke so I drove it home with no problems.I was gasing the car at home and noticed that it is smoking from I believe where the spark plugs area,is this a gasket? I know the car does need a heater core,tuneup and an oil change.I just changed the tensioner pulley last week.If anyone has an ideas as to what this could be or if they are related please let me know.This all started the first day of school and I need to get it fixed so I can get my child to school.