headphone

Im wanting to build a converter from RCA audio to 3.5mm out with a volume control. does anyone know how to do this exactly?

A friend of mine wants to hook up his electric guitar to a pair of headphones directly plugging it into a fuzzbox, and if possible, mix in his iPod music such that he can play along with the music without disturbing anyone else in the house... It doesn't need to be very Hi-Fi. The circuit needs...