Yep, basically you create a new user, if you don't want them to be able to log in to the shell edit their line in /etc/passwd and change their /bin/bash to /bin/false
Then have your directory
/srv/www/my-domain.com/public_html/*
you make sure root owns srv, www, and my-domain.com
The user needs to own public_html and the files inside of it
then edit /etc/ssh/sshd_config per the instructions
set their chroot directory to /srv/www/my-domain.com/
When they log in they will be resticted to my-domain.com and whatever folders are inside of it, including public_html.
Hope this helps, write back if you have any more questions.
