A few months ago I was looking for the website monitoring services and registered at Host-Tracker. Today, thanks to its notification, within 5 minutes we found that our server is down and fixed the problem.
The service is free and you can configure multiple servers and test them every 1, 5, 15, 30, 45, or 60 minutes. You can test individual URLs using HEAD, GET, or POST methods.
Host-Tracker uses servers in different locations to perform testing, including
- Dallas, TX, US
- Moscow, Russia
- Brisbane, Australia
- Scranton, PA, US
- Atlanta, GA, US
- Portland, OR, US
You can choose to be notified about the problems via e-mail and SMS. The website also lists Google Talk and ICQ but I couldn't get them to work with Adium.
Overall it is a great service. Recommended.
http://host-tracker.com/