Think of different user accounts on a computer like having multiple computers. Log in to your wife's account- sync her iPod with her iTunes library- log out. You log into your account then sync your iPod to your library.
Each account has it's own home folder wich holds music (iTunes), movies, photos, documents. They are all separate. The only thing shared between accounts (by default) is the applications folder.
Just remember if there is some music your wife has in her iTunes library that you also want, you will need to put it in your library as well- and this will double the disk space used for those songs.
10-10-2011 09:15 PM