2002 Chevy Camaro valvetrain noise

There is a very loud tapping noise coming from the front of the left valve cover. It began as a very loud chirping sound but now has settled into a constant, very loud tapping noise that changes with the rpm of the engine. The engine, however, performs as new, though I doubt it will for long as it seems doomed unless I fix the problem. Please give me an idea of what to expect.