[PHP-DEV] Extensions building tutorial

[Artzi, Yoav \(Yoav\)]

I am looking for a good place to learn about the following:
1. Writing a customized extension
2. Compiling PHP with customized extensions, including how can I set up
a customized location their code and what I should add to the configure
line and such
 
Any good tutorials out there?
 
Thanks.