Peek-O-Matic is a free AppleScript which allows you to run an application as another user. You bind an app permanently to the script by drag-and-drop and then it asks for a user name and remembers that, too. Henceforth, launching Peek-O-Matic launches above app as above user. You can choose whether to enter a password each time or have it stored in the Keychain.
Mall Creeps
