Block users from accessing wp-admin page. Disable the WP Admin Bar in WordPress 3.1+. And redirect users to home page.
This plug-in will disable all users (subscriber, contributor, author, and/or editor) except administrator from accessing admin pages in your wordpress. That mean after activating this plug-in only Administrator user will be able to access wp-admin page. Also this plug-in will hide the dashboard bar from users. If the user is admin then only the admin bar will be shown. Note: To work this plug-in you need to have a minimum of WordPress 3.1. Other version have not tested yet.