If you're in the web application development world, you know what LAMP means; for everyone else, it's Linux/Apache/MySQL/PHP, the core technologies of gazillions of websites and the defacto "standard stack" for any database-driven project. While every Mac OS X Server install includes all the AMP components, and you can easily install the missing pieces on a standard OS X configuration, it's always nice when someone goes to the trouble of putting everything together in one handy package.
The kind people at living-e (makers of webEdition and timeEdition) have been making that handy package for a while now in the form of MAMP, a free bundle of the AMP tools that runs as a standalone website, separate from the default Apache configuration. MAMP is intended for prototyping and development but isn't powerful enough for production use. Now, living-e raises the ante with MAMP Pro, shipping today (price
TBD$49 US). The pro version lets you set up unlimited virtual hosts, with individualized MySQL and PHP "sandbox" configs; you can even choose to run sites on PHP 4 or 5, depending on the target environment. The new setup tool also allows you to register your servers with dynamic DNS providers and set up the postfix email server to test mailer scripts.
If you've got several projects cooking and you need more capable prototyping than the built-in Apache server can deliver, MAMP Pro might be a good option. As some readers have pointed out, you can accomplish some of the same tricks by combining the free MAMP with the Headdress sandboxing tool, or with the (still in early beta) XAMPP package; your mileage may vary.