It would help to know where it's coming from. If it's a rear main seal, you can wait 'till the next time you've got to do the clutch, or until it gets really bad if it's an automatic. If it's a front main or an intermediate shaft seal, it's a lot easier to tackle, and if it's a camshaft seal that's even easier.

It would be a good idea to make sure your flame trap is clean and your crankcase ventilation system is working right - start the engine and loosen but don't remove the oil filler cap. If it dances and jumps around, you might have excessive internal pressure caused by a PCV blockage, which is forcing oil out the seals. This is a pretty lame test, because not much blowby happens at idle and the oil cap can appear to dance if the car doesn't idle smoothly.