"One man, one vote" ... or the techno equivilant of "One computer, one ipod".
An ipod can only be connected, or synchronised, to 1 itunes software on 1 computer.
You can have 100 ipods synched to the same itunes, but
the only way you can share music is by opening my computer and click and drag the file into the ipod directly.
(this is what I had to do to share my 20gbs with a mate)
Then you hook your ipod up to his, or her, computer, open my computer, open the ipod, highlight all the files and paste them into his, or her, folder.
And vice versa if you are wanting to share his, or her, music. But DO NOT copy and paste files from itunes. Go in to the folder itself, select all and copy and paste (or drag) from there. Annoyingly, itunes codes the title to a 4 letter prefix which can only be decoded if then played through another itunes.
*dabs forehead*