Sorter

Sorter is an application that allows you to organize your files automatically. It has the ability to leverage Mac OS X's Spotlight technology to organize your files efficiently based on their contents.

With this tool you can watch a directory for changes, define criteria for events to react to - including the file's contents, its name, size or date, or even the type of the event (create, delete, rename...), as well as trigger multiple actions per event (move or delete a file or run your own shell script to do whatever you would like to do).