What is the best way to hook a portable music player up to an old 2-channel stereo?

I just bought a Cowon that handles lossless (FLAC) files (it's like an IPOD, sort of) and I want to hook it up to a Marantz old-school 2-channel stereo receiver. What is the best way to do this? Can I just use a stereo headphone-plug to y-RCA plugs adaptor? Thanks.