to add Openid authentication to your dbscript application, simply use the command authenticate_with_openid() in one of your controllers and the controller will not proceed until Openid authentication has been established.
$_SESSION['openid_url'] will contain the user's Openid, which you can use to remember them in your people table, and give them full read/write access to any comments or other content they add to your site.
when their session expires, they will have to provide their Openid again, but they won't have to put their password in again unless they didn't choose the "always allow" option at their Openid provider.