Hacking GIMP - Gimp top level menu

Hi,

I was wondering how the top level menu for GIMP is created (The one with these items: "File", "Edit", "Select", "View", "Image", etc. ). I want to add a menu item to this menu and I'm kind of lost as to where to start. If someone could tell me where to hunt around in the code for this and give me an explanation of how it's done, that would be great! Even better, is there some documentation online about this kind of thing?

Thanks in advance,

Jordan