There is! That is, if you have a regular iPod... You can get a special wire that plugs into the usb thing, then trainsmits the music to the other ipod.. it's kinda confusing and i can't explain it well, all i know is that they showed it on Attack Of The Show/ The Screen Savers (it was Kevin Rose who did it, i believe)...
also, try this:
http://www.topshareware.com/iPod-2-i...load-39933.htm