I'm a web developer and I use a Mac. One of the first things I had to do when switching to a Mac was find software that allowed me to develop websites locally (on my computer as compared to on the web). Setting up a local server is usually a difficult task, requiring programming and advanced networking knowledge. However, I came across MAMP and it saved me!
I was very impressed to find out that MAMP is completely free software. There is a MAMP Pro version, but it has advanced features that I would rarely use, so I stuck with the free version. The free version of MAMP comes with a mysql server and is able to parse php and other web languages. It's absolutely perfect for the work I do since I generally develop templates for WordPress.
This software doesn't technically come with support, however there is a vast amount of information in the forums and people are always helping each other out. Plus, the software is so easy to use that it's practically self explanatory.
Installation was a breeze and installing websites is even easier. MAMP comes with PHPMyAdmin built in, making it extremely easy to manage databases. Switching between PHP 4 and PHP 5 is easy as well, all it takes is a click of a radio button.
If you're a web developer, or someone just interested in making websites on your computer, I would strongly recommend MAMP. It's free, easy to use, and saves a lot of time!