Noodlesoft has recently released Hazel 2.2, a nice update to their rules based file organizer. Hazel 2.2 adds a number of interesting AppleScript improvements. You can now add scripts directly in rules, no need to create seperate files for your scripts. There are also some new Hazel specific AppleScript keys that allow you to pass values from a script to Hazel, which really lets you make some imaginative rules. You can check out the full release notes to marvel at all the updates Noodlesoft managed to cram into this point release.
Hazel is one of those applications that is tough to describe, but once you get it you'll be amazed you managed to keep your Mac organized without. Hazel costs $21.95 and version 2.2 is a free upgrade.