How do I use Google Chrome 11's Upload Folder feature in my own code?

You should be able to see a demo here: http://html5-demos.appspot.com/static/html5storage/demos/upload_directory/index.html

Basically it works by setting up an attribute "webkitdirectory" on a file input element.

<input type="file" id="file_input" webkitdirectory="" directory="">

Then when the user has selected a folder, it itterates across the "e.target.files" object to get a list of files included in the selection (this enables you to have access to those files from the clientside).

Drag and drop is similar, when you listen to the "ondrop" event on a "draggable" element, if a a directory or selection of files is dropped on to the element, the "files" property on the event will be a list of files contained in the operation.