Mac OSX has become extremely popular for Ruby on Rails development. Part of this is the inclusion of Ruby as part of the operating system on Mac OSX Leopard. Here is a quick tutorial on how to get Ruby on Rails and MySQL set up on your Mac OSX Leopard machine. In order to complete this tutorial, you need the Xcode tools installed. You can get them off of the applications disk that came with your mac or from http://developer.apple.com/TOOLS/xcode/.