I documented this leak with pics so it will be easier to diagnose. Looking down on the engine bay < http://img98.imageshack.us/i/img0516r.jpg/ >, the leak is towards the rear firewall on the driver's side.

Over near the motor-mount, just beneath that ground wire is where I think the leak begins.

Here is a pic of the leak just below the ground wire < http://img710.imageshack.us/i/img0510ae.jpg/ > and below the 13 mm nut.

From below you can see the oil dripping near the O2 sensor: < http://img341.imageshack.us/i/img0513u.jpg/ > and coming out near the fuel lines < http://img46.imageshack.us/i/img0515fi.jpg/ >

Also, but it doesn't concern me as much, is the film of oil I wipe off from time to time near my filler cap. Should I be concerned about that?

Also, as I was looking around, this fell out of the engine bay < http://img21.imageshack.us/i/img0527rk.jpg/ > . What is that?

 

I'm having a little trouble by looking at your second picture, The most common place for them to leak in that area is from the camshaft oil seal. Your camshafts protrude through the head and one turns the distributor and the other has a sensor on it I think. The oil seals need replacing every once in a while. Pretty easy job to do yourself.