Free Site Monitoring from Comodo
Comodo Sitemon is a free website uptime, continuity and availability monitor and checker that automatically checks your website is up and running and viewable by your customers every ten minutes, 24/7. SiteMon also monitors user-selected keywords and the title to ensure your web page has loaded correctly and content has not been modified. Any problem will be alerted via email.
This is a must have for all webmasters.