Are My Sites Up is a very simple service to help you keep an eye on your sites and warn you if they go down. It is completely free.
Sign up for an account, add your sites, and you are done. You can pop back to the site anytime to get a quick look at your sites. By default, you will be notified by email if any of your sites goes down. Optionally, you get an SMS text notification to your cell phone.
Last updated 15 Mar 2010