www.informit.com/articles/article.aspx?p=24592

This is a short tutorial on how to use cookies with PHP

kb.mediatemple.net/questions/36/Using+Environment+Variables+...

This article tells you how you can read apache enviromental variables with PHP.

baglan.web.tr/watermarking-php

This shows you how to watermark your pictures on the fly. There is also a version that has a cache. This also uses .htaccess

www.alternateinterior.com/2007/01/what-is-_request.html

An article called,  What is $_REQUEST, or the difference between $_REQUEST, $_GET and $_POST?

www.totallyphp.co.uk/write-data-to-a-text-file

this gives you the code on how to write text to a file using php