Install Apache, PHP and MySQL on Mac w/o MacPorts?
Yes, Apache and PHP already come by default with a Mac OS X installation, and you can download an installer for MySQL on their website.

For a configuration guide, have a look at this related answer:

How to turn Mac OS X Lion into a web server?

The linked answer also applies to Mac OS X Snow Leopard.

Another popular (and imo superior) way of running development environments is running a Linux server with your preferred configuration in a VirtualBox virtual machine. Vagrant makes this workflow even easier. This is a very flexible solution, as you can easily add custom extensions and more specifically for one project, without messing with one centralized install.