For cPanel users can login in any of the following ways:
 

• They can go to http://theirowndomain.tld/zen
• You can provide a login button on your site that targets a new window with the url http://hostname.tld/zeni/user_type=user
• You can automatically add a siteZen ICON to cPanel skins as follows

cd /usr/local/sitezen/prd/cpanelscripts
./cpanel_updateskins.sh 

(this must be done as root)

• If you are using 3rd party skins that allow you add your own icons icons (e.g. RVSkins) you should run the script as above and then add an add with a URL of cells/sitezen.php