Make sure it's the oil pan before pulling it. It was about a 16-hour job to pull and re-silicone mine only to find out that it was a broken head bolt causing the leak.
Shine a flash light down into the valley under the intake manifold and make sure there isn't any oil pooling in there. The way it runs down, it looks like it's coming right out of the oil pan.
If that doesn show the source, clean up your engine then pick up a UV leak detection kit at Autozone. They have a small setup for around $15.