This most excellent plugin does a fine job however, I had to delete the plugin using my FTP client and go into PHPmyAdmin to removed the plugin tables as it did not play nicely with another one of my plugin... http://wordpress.org/extend/plugins/clkercom-clip-art/
WP-Sentinel saw an image being placed from one of my posts and did not like that the image did not reside on my server by was accessed through the clker.com server. I got blocked out of my site while logged in as an admin. Ouch.
Anyway I have moved on to http://wordpress.org/extend/plugins/secure-wordpress/ but I still beleive you an excellent plugin here, just not to friendly of a WP plugin setup options, I am more of a security novice.