a screenshot wouldnt really add any information
just look at the bottom of your forum for this line:
Log Out | Mark All Forums Read | Forum Leaders
and imagen that with the hack installed it would look like this for an admin:
Log Out | Mark All Forums Read | Forum Leaders | Admin CP | Mod Cp
or this for a mod:
Log Out | Mark All Forums Read | Forum Leaders | Mod CP
basically usegroups that have access to the admin control panel (you can define this option when editing a usergroup, I think its the last or second last option) will see the admin cp and mod cp links and usergroups that are defined as moderators will see the mod cp link.
the only difference with this 'hack' compared to the template modification posted on vbulletintemplates.com is that in this hack the script automatically detects a usergroups permissions and with the template modification you have to define the usergroups manually.