itunes, when moving the music across to the ipod, shuffles up all the songs and distributes them into folders each containing 50 or so songs. it renames all the songs along the lines of "026.mp3" etc and then names all the folders in a numerical order, "14" "35" "51" etc.
it then makes all the folders and files hidden.
you aren't meant to find them, or access them directly in any way.
some software will let you access these folders, some will let you browse them properly, but none make it particularly easy.
do a search on the web for a program called yamipod, it is good for copying music from your ipod to the hard drive. Can be used on windows or mac. You can save the program onto your ipod and just run it from there.