Toggle Guest Access is a handy application combined with an Applescript Studio tutorial. January's MacWorld contained an item about turning off the guest access that is turned on by default in OS X so that the dropbox in the Public folders can be used. A brief tutorial is included, describing how to turn the Applescript into an Applescript Studio application. In the AS-Studio version, your password appears as bullets, while in the Applescript version it appears as clear text. This should toggle guest access preferences if you've ever activated file sharing.