Hey guys, my wife just called me and said my sidekick sport is leaking oil slowly from between the engine and transmission.  Any idea what it could be?

Several possibilities exist ...

First - is it transmission fluid or engine oil?

If it's transmission fluid - the transmission input seal

If it's engine oil - engine rear main seal, cam position sensor (there is an external O ring, and I believe there should be an internal seal) or the cam cover gasket.

A slow weep from the cam position sensor O ring is fairly common, and is more a nuisance (because of the dirt) than a problem - the oil loss is insignificant on mine.