[Zope] Authentication - login/logout

Does anyone know how to logout a Zope user? Basically I need to be able to force an authenticated user back to the 'Anonymous' user programmatically. (when someone presses a logout button, etc.) Also, how can I change the message text in the login popup window? Currently it says something like, "Enter username for Zope at foo.bar.com:" I would like to be able to modify this depending on where someone is logging in. Thanks - Wade wsimmons@ep.newtimes.com Disclaimer: opinions expressed in this email are not necessarily mine or anyone else's.