Google Workspace provided an automated tool http://www.google.com/support/a/bin/answer.py?answer=33561&topic=15894 which will help you to reset the Google Workspace admin password.

You can also access your Google Workspace admin password reset page by visiting the login page for your domain (example: http://www.google.com/a/yourodmain.com) and clicking on “I cannot access my account.” if you get a message which says contact your administrator, then you are actually at wrong URL. that particular URL is a users login page, not the admin login page. please check the URL with the above one.