I stumbled on MAMP this weekend when I couldn't figure out why my Apache installation on the Mac no longer seemed to support PHP.
MAMP stands for: Mac, Apache, MySQL, PHP and is basically the Mac version of the LAMP stack. The thing I enjoyed is that it's a drag and drop install and you have the whole stack live with no configuration necessary. While it's not really for production it's much easier than having to navigate some of the intricacies of Apache (not that IIS is any easier, despite having better GUI tools) for development.
Anyway, it's a useful utility and comes in a free and paid premium version.