Is your oil drain bolt/washer leaking?
What kind of oil did you use before/after?

Gently wash the engine/bay (cover your distributer, wires, intake) and the ground, lay some card board down under the engine, and see where it's dripping from. Then you can pin point the leak and fix it.

As far as the overheating, does it overheat when you drive (cruising on highway) or when your sitting in traffic, or when it's just idling? Could be a number of things.