Hi DRtothE,
It's the Rear main seal most likely if its engine oil, otherwise it's proberbly the input shaft seal if its tranny fluid leaking.
If it's pissing out oil, then the clutch will have become contaminated. The longer you leave it, obviously the worse it will get.
I would just remove the driveshaft and transmission and have a look at clutch while your in there.
Let me know if you would like part numbers for a clutch kit and rear main seal.
Just before I forget what is your vehicle build date - eg 03/93? and also what vehicle do you have?
Good luck