MAMP — Macintosh Apache, MySQL and PHP
MAMP is the MacOSX equivalent of XAMPlite, the software some people in the class are using to ease PHP work somewhat by removing the need to upload the .php file after every change.
This is because both XAMP and MAMP put a temporary web server on your computer while, allowing you to run .php files from your computer. It also runs MySQL for the more advanced php/database work.