I was using Apache2Triad for a long time but I found a server called Uniform Server. This is a tiny(20-30mb) server which includes Apache MySQL and PHP.
I will be happy to see this program in portableapps.com.
Here is an explanation form http://www.uniformserver.com:
The Uniform Server is a WAMP package that allows you to run a server on any MS Windows OS based computer. It is small and mobile to download or move around and can also be used or setup as a production/live server. Developers also use The Uniform Server to test their applications made with either PHP, MySQL, Perl, or the Apache HTTPd Server.
You can join our forums(http://forum.uniformserver.com) for help and donate ofcourse .
Note: My aim is not advertising.