Visualping - Visualping is the easiest to use website checker, webpage change monitoring, website change detector and website change alert software of the web. Read more about Visualping.
Ping Meter Gadget - Customizable, graphical, semi-transparent ping (latency) meter.
Distill Web Monitor - Distill is a web monitoring tool. It can monitor RSS feeds, a webpage or a part of webpage. Alerts in the form of pop-up, audio or emails can be received.
Fping (open source) - fping is a program to send ICMP echo probes to network hosts, similar to ping, but much better performing when pinging multiple hosts.
Update Scanner - Update Scanner is a Firefox extension to monitor web pages for updates.
PingDoctor - PingDoctor is software that is considered to be the most powerful and easiest to use network route analyzer.