A few weeks back Amazon released nice little tool called SendToKindle.
After you installed it on your Windows PC, it gave you the option to right-click on certain files and send them to your Kindle. It's a neat little tool, but it is also restricted to just Windows. If you're running Linux or OSX, you're out of luck.
The German ereader blog e-book-news.de has pointed me at a new web app that works with Dropbox. You can use this tool to automate a number of activities, like converting files, uploading images to Flickr, and you can tell it to autocratically email docs to your Kindle account.
Pretty cool, huh?
I'd say that this actually works better SendToKindle. Not only is the process simpler, but you also end up with an online backup copy of your content. It also puts you in the mindset of keeping an online backup, which is also a plus.
So how is it simpler? Rather than having to right-click on files, you can upload to Dropbox (and thus trigger DropboxAutomator ) simply by dragging files to a shared folder. You'll first need to install the Dropbox app, but you should do that anyway (it improves upload speeds).