Monitor Uptime/Downtime of Site

Here is some site links which shows Uptime/Downtime of your site.

(1) Free website monitoring, receive 24X7 website monitoring email and sms

(2) WhenDOUP!

(3) Notify Mee

(4) Are My Sites Up?

(5) free web site uptime monitor service - server and network failure alerts

(6) Mr Uptime

(7) Pingability.com: Web Site Monitoring and Alert Service

(8) Website Monitoring, Website Monitoring Service, Server Monitoring: Site24x7

(9) Observu - Site & Server monitoring