Antifreeze going down ever so slowly

If my antifreeze is slowly disappearing, how do I find out where it is going? What are the possibilities? Obviously, I can't see any leaks. Oil looks fine, car runs fine, tail pipe isn't "wet," etc.

Check the waterpump. It may be seeping through the weep hole indicating that it will soon go bad. If there isn't any coolant there you may have a small leak in the radiator. Also check the hoses, they may be slightly loose and only leaking when the car is cold. The coolant recovery tank is also a possibility, it could have a leak as well. Finally, check the pcv valve, if it is cream colored or has what looks like cream on it you may have a bad manifold gasket.