Have tried a couple of things in the past.
1) If the spill is outside where the sun can reach it, put down several layers of newspaper and soak the paper with water.
Hold paper down with some bricks and let the paper completely dry up. The oil gets pulled into the paper when the water evaporated.
2)Have some absorbal around all the time, these granuals will soak it up.
3)Simple Green will clean up the rest.
Check out this web site:
http://www.homestore.com/Cargarage/Garage/Fstained.asp