Read the full userguide here: http://massivecraft.com/dev/creative-gates
Download the latest jar and put it in your plugins folder.
We are open source so you are most welcome to join the dev-team :)
This plugin uses the framework MassiveCraftCore.
Please take a look at the readme file for that framework.
There are important info for devs.
This project has a LGPL license just like the Bukkit project.