Uniform Server is a bundle which includes Apache2, MySQL5, Perl5, PHP5, phpMyAdmin and more, and makes it easy to run a web server - either development or live - from just about any Windows PC.
The program is a surprisingly compact download at 15MB. It's a self-extracting archive, too, so all you have to do is run it, specify a folder and everything will be unpacked there.
Check the UniServer folder and you'll find three further executables: "help.exe", "Start_as_program.exe" and "Start_as_service.exe". Again, it's fairly obvious what you should do, but running "help.exe" provides more details, if you're interested. Otherwise just launch "Start_as_program.exe" to take a look at how everything works.
Uniform Server doesn't require any complex installation, so you're not left on your own trying to figure out some MySQL issue, for instance. Simple alerts explain what you need to know about a few key issues, and within a few seconds you'll be looking at the main Uniform Server console. You can start Apache with a click, and immediately you'll be able to try out PHP or HTML pages just by copying them to your UniServer\www folder.
This isn't just for development, though - you can use Uniform Server to run a live web server, host your own websites and make them available online. This does require a lot more thought and configuration time, but again the package does a good job of helping you through the setup process.