How to create a code a new Project/IDE Setting?

This may seem like a pretty basic question, but I've been digging through examples and I can't find a clear example of how to code this up.

Basically I want a couple of prefernces for my plugin - one in the IDE settings, and one in the project settings, and I can't see how they get configured.

Is it part of the XML file that needs to register the class, or something else? I can't find any documentation on this.

I've been using the La-Clojure plugin for some good examples of implementing some of the things I want to do, but I can't seem to find where in the plugin.xml everything starts for adding to the Settings dialogue.

Any help to point me in the right direction would be greatly appreciated.