Here you will find some demo applications (created by Matthijs at Kadijk dot com) using the google docs API.
The first demo is a simple user interface that enables you to SHARE folders in Google Docs !
Try it out here ... You will asked to login using your Google account, and than to give the app permision to access your docs. You will get a list of your forders and the sarring properties of these folders. Start sharing your folder using the "share this folder" button. You can change / remove the sharing properties using the buttons.