Clayton:

If it's just a trace, you might want to drain and flush your entire cooling system. Drain radiator, engine block, forward and back flush with a hose. I've even read of people using dish washing soap to degrease engines with, but one does this after the repair.

This is what I'd do before spending $$$$ on a head gasket. Then again, this could be the early stage of a leaking head gasket?

There's been alot of talk here about oil-in-the-water. You might want to SEARCH around here for more ideas.