Thank you for your help jeff.
The way I ended up doing this--incase anyone else wants to know is:
1. Create the user (exp. joe)
2. Create A group for the user (exp. joes_users)
3. Create the I-bay for the users website, setting the group to "joes_users," and then choosing writable by group and readable by everyone. and then "Entire Internet" access. finally enabling exucation of dynamic content.
4. Lastly i created a virtual domain for the website.
This will give the user a e-mail address and public ftp access to their website that is only writable to them, not other users.
Hope this information helps clear up future questions from users, please let me know if what i just explained is not the preffered way of doing things--or if there is a better or more effient way.