Title says it all. I'm looking for an app that will do a bidirectional sync between an external drive and a single folder on my Mac. Even better if it will automagically recognize the drive when I plug it in and do everything without being asked or told where to look... just like iPods in iTunes. This is specifically for my Kindle. It mounts as a regular ol' external drive. Because I download some books wirelessly from the Kindle Store, and others are from various websites (like feedbooks) that I download and transfer via USB, the larger my libarary gets, the harder it is to sync manually. (And I want bidirectional sync in order to keep a copy of all my books, clippings, notes, etc. backed up on my Mac & its backup.) So anyway... any tips? I'm not looking for anything super-complex. No scheduling, no fancy interface. Just "when you see this device, sync it with that folder." Cheap is good, free is better. (Doing it within the OS is better still! Automator, maybe?) Thx!