Guys, the OP also said he had turned off the fuel when the leak occurred. I agree it sounds like the float valve is faulty and replacement is the way to go. Clearly, the shut-off valve is also leaking. This is also an easy fix. I recommend:
http://www.snydersantiqueauto.com/gas-valve-repair-kit
at $1.60, it is very cheap, easy to install and works well.
He also mentioned an oil leak and wondered about the return pipe leaking. I suggest taking the pipe off (2 small bolts) and inspecting the seals replace if necessary or use some permatex on both sides of them them before reinstalling.