This plugin can be download here: ntop-v0.2-1.tgz
Provide an iFrame to point to your NTop Server
As per all 2.x Plugins, extract in the plugins directory and install/enable from Plugin Management
Goto Console→Settings→Misc and setup the URL, grant your users access to the NTop Realm and NTop away.
If you need additional help, please goto http://forums.cacti.net