My son's car leaked oil on my driveway and it has soaked in. How do I get that stuff off? Is there a spray or something? 

You can pee on it.

But that won't do anything, it would just be funny. There's nothing you can do for an oil stain that you can buy from a store. A power washing will do it. Lawn Scaping people usually do that service. Might as well have them do your fence and home while they're there since hiring them for a driveway spot wont' make $$ sense. 

here's nothing you can do for an oil stain that you can buy from a store.

Incorrect... An emulsifier and scrubbing will go a long way to removing it, although maybe not completely. 

link 

Gas stations use cat litter to absorb gasoline spills etc... Maybe it'd work similarly? Might be worth a try at the very least? 

cat litter works great, we had a car leak in our driveway, we put down a full bag and it soaked it right up... the stain is still there but no more oil residue 

Saturate the spot with gasoline, sprinkle it down with Comet or Ajax, wet it a tad and use a push broom or scrub brush to work it out. Should be able to hose the drive way down afterwards and most if not all of the oil will have been dissipated. If it's an old "black" oil stain that has been there for a while, do the same as above initially, but you'll need a pressure washer to work it out. Hope this helps. It worked for me when I accidentally spilled 1/2 of the oil pan out after an oil change. 

Kitty litter will remove fresh oil, as will Tide laundry powder. (That's what race track clean up crews use.)

Tide powder, with bleach, may pull up old oil stains if you wet it enough to make a paste, and then scrub it with a stiff bristle broom.