Sucuri is a cool new security monitoring service for web site owners. The service will scan your website at regular intervals and notify you instantly by email (or SMS or Twitter) if there’s any dodgy stuff going on with your site.

Unlike conventional site checkers like Hyperspin, Sucuri checks for things like DNS hijacking, blacklisting, site defacement and malware injection which is awesomely useful if you need to know fast if the baddies have attacked your site surreptitiously. Best of all it’s free. Definitely a hugely useful service.