ls2.gto

I've recently noticed that i've picked up a small oil leak on my GTO, and can't seem to trace it back to anywhere and it's driving me freaking nuts! i'm not losing a visible amount of oil when I check the dipstick, but my skid plate has oil reside and the occasional droplet of oil seeping thru. any ideas? I can't find any traces of oil above the skidplate and didn't notice anything when I removed it.