Where to find a complete "hello world" example/tutorial for XBMC addon development?

I'd like to start studying xmbc plugin development.

I read official documents, but I'm asking you if there are some resource taking a really step-by-step into an hello-world example.

I google for very long time yesterday and today but I'm not able to have a full picture of the development process.

I'm looking for detailed information about:

• directory structure
• creating the simplest GUI for an hello world (no alert, a Window)
• code with explanations
• creating a zip
• installing via repository
• ...

The best resources I can point to is: http://wiki.xbmc.org/index.php?title=Add-on_development

It provides a lot of information which should be good for your first steps.

And of course the forum is a goog place to gather information: http://forum.xbmc.org/forumdisplay.php?fid=26