Is It Down Right Now? - Network & Admin
ServerSuit - ServerSuit is a browser based program that enables remote Linux administration, monitoring, website hosting, and server setup automation.
UPDOWNtoday - UPDOWNTODAY allows you to check whether the website is down or not.
AppZero - AppZero is a monitoring and migration tool that allows users to keep track of different applications and servers in both simple and complex IT environments.
Site Down - Site down outage and downtime reports from SiteDown.co
CULA - A webmonitoring solution for beginners and pros.