Funny you would ask about this, I just replaced mine to sold a somewhat ambiguous leak I have. I did my timing belt and forgot to silicone the valve cover gasket on round three of getting it all together (it was my first one and I screwed a couple of little things up I had to tear down for). Anyway, there was oil runoff from that, but it also looked like I had a distributor leak. So I pulled the cap and the distributor itself was dry inside, while the it seemed to be leaking between the distributor and head. I got the new seal for $2.73 out of the Honda parts dept, replaced it, and now I need to steam clean the engine and see if between the Hondabond on the valve cover gasket and the new O ring I fixed it.
But be SURE to take a knife and mark a line across the mounting ear on the head and the distributor body so you know what position it's in before you remove it. if you don't do this, you will probably have to retime your engine (not fun at ALL).
So, assuming the oil leak is external, then that seal is no big job. If it's the shaft bearing, you probably have to buy a new distributor. I know a guy who had the distributor seal/bearing blow out on the highway in his 93 Special Edition EX, and it blew oil into the cap and killed the ignition obviously. The mechanic had to install a new distributor.