Operator, though as tactful as a flame-thrower, is usually right. The first thing I thought when reading your query was: Has he checked his bottom-bracket? A tick, tick, tick - and getting worse - sounds like a BB. Or a problem with the chain. Or any number of things. I'd start there before pumping the frame full of pressurized dye.

Try this:

http://sheldonbrown.com/creaks.html