Does the Framework Documentation exist?

Is there any documentation on the whole opencart framework?
I'm new at this and trying to figure out how the whole framework works so I can write my own modules.

The framework is based on the MVC concept. So the structure is:

In catalog:
controller/xxx.php
language/english/controller/xxx.php
template/default/content/xxx.php

Additional dcumentation is not there yet but is planned for the future when OpenCart reaches that 1.0 mark. For now, take a look at some of the community created contributions on the http://www.opencart.com/contribution page to get some examples of how to create them.

Since OpenCart is already a google code project and the Wiki page http://code.google.com/p/open-cart/w/list is empty, would it make sense to begin creating some documentation of the internal structure of OpenCart there?

But, it might be better if there were a separate google code project just for the internal program structure.  This would make it possible for you allow anyone who would like to contribute to the documentation to sign up as a project member.  It could be named something like "open-cart-doc-internal".

If such a thing had existed, it would have saved me hours (possibly days?) of development time.  If you create it now, it might save the author of the next killer OpenCart contribution a lot of time, too.

I envision an initial wiki page structure something like this:

• OpenCart Overview
• • Controllers
  • Templates
  • Modules
  • Languages
  • Library
  • • Locator
    • Cart
    • Database
    • Request, Response, and Session
  • Extensions
  • • Module
    • Calculate
    • Payment
    • Shipping

The structure is changing in 0.8, and the plan is for that structure to be the final framework design for future versions. So we are waiting for that to be released before adding documentation.