It looks as if our spam filtering service, postini, is experiencing some problems with their login page at the moment. If you get an error message when attempting to log in to postini, don't be alarmed, we will update the support blog when the situation has been resolved.
UPDATE 8/23 (8:00AM PST): As of this morning, postini logins seem to be working. If you have any further problems, please contact us at support.