Gayan at http://gunemalli.blogspot.com/2008/04/some-cool-web-montoring-websites.html reviewed several web sites. In your words:

“http://mon.itor.us/
And finally the best of all the free web monitoring sites, mon.itor.us. This site has all the monitoring features a webmaster would want. Charts, graphs, internal monitoring, benchmarking and many many more from this site for free. This is something that you should have definitely.”