I have written a PHP module in C. What are the rules of including this in PEAR?

Answer written by Stig Bakken and Martin Jansen.

If you just want to make a simple extension that does not follow the PEAR coding standards, put it in pear/PECL/ extname (that is where extensions from php-src/ext/extname will be moved). If you want to write an extension following PEAR's function/class naming, put it in pear/Foo_Bar or whatever the right name is.