Currently Being ModeratedFeb 21, 2013 11:52 AM (in response to JasonDecall)
The installation of OS X Server and MAMP are completely and totally different, and the software versions involved are different.
As you're probably aware, OS X Server 10.6 already contains MySQL, php, Apache and related, and (for this part of the OS X Server environment) administrative interface known as Server Admin.app.
If you want to use MAMP, you'll have to shut down those parts of OS X Server, if that's what you're using. Only one application can be active on a port, such as Apache on TCP port 80. In particular, you'll have to launch Server Admin.app and shut down the services you want to use from MAMP. Once you have these components of OS X Server shut down, then you can install MAMP as you would on OS X client.
If you don't want to shut everything down, you can use MAMP on non-standard ports; I haven't tried that with OS X Server, but it works with OS X client. (OS X client also includes Apache, and can have that active on TCP port 80.)
FWIW, MAMP is generally not recommended for use on production sites and on Internet-exposed sites. It's set up for use during development. OS X Server versions are set up for use in production sites, though 10.6 itself is getting old.