Uniform Server
http://www.uniformserver.com/(Taken from website)
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.
Now I've used both Xamp and Wamp, personally i preferred Wamp just gave me less headaches over all, but i was googling and found this lil gem, because I take my code with me to work on a thumb drive, I am constantly changing between my home desktop and my laptop, this was perfect.
I simply download the Uniform file,run it, which extracts to say your thumb drive, the file structure looks nix based, but easy enough to find the "www" folder us wamp users should be familiar with run the application from the thumbdrive start the services and tada your off and running entirely off the thumb drive.I will say my setup is rather slow mainly from the drive I am using (its a old USB 1.0 256MB drive i had laying around doing nothing)Which fits with plenty of room the server, all of what i bring with me back and forth and even a copy of the php manual. There was also a few plugins php 4 etc and other things on the site but the reason i had actually found the site to being with is I was looking for a wamp/xamp setup with CVS or SVN that could be installed on windows, But I figured i would share this with everyone seeing how simple it really was to get up and running and am actually quite curious if something with a bit more experience could take a look at the wiki they have and look over the SVN, because i believe with ease of use and SVN Some of us beginners/Intermediate coders really couldn't ask for a more professional environment.(yes i have a nix box, but i don't even pretend to fully understand it yet)
Edit:
Having had it up and running on my laptop the last few days i decided to try it on my desktop(been slacking on desktop time, was using it to watch movies and working on laptop) Long story short, it was not working initially and a very quick visit to the forums, revealed diagnostic tools built in, and a quick scan through a readme and tada desktop is now running it as well.