Danne Lundqvist has a new post today showing you how to install and use XDebug with MAMP, the popular all-in-one LAMP package for OS X.
MAMP is a full local server environment including Apache, PHP and MySQL in one package. Anyone feeling at home in *nix systems should feel at home using both OS X and MAMP. [...] As I have helped a few collegues setup Xdebug in MAMP I have discovered that a lot of developers don’t do this as they don’t know how simple it is. Even seasoned PHP developers use the old echo/die debugging techniques.
He includes all the changes you'll need to make to configuration files and makes a simple script you can use to test out that things are working. As his IDE of choice is PHPStorm, he shows how to set up the remote debugging to work and reply back as the script is executed.