Plugin Info

I'm looking to try and develop a plug-in for Textmate and was looking to find some good downloadable examples or tutorials. Do you know of any or can point me in the right direction.

Thought I'd add a little of what I'm trying to do:
When the user selected a file from the panel view, it is passed to my plug-in where I can get the extension value and do something with the file.

I've downloaded the clock example but it seems to simply add itself to the window menu item and display a window with text.

Hope you can help out,
Thanks.