In need of web site monitoring software

Intranet monitoring only - no "thin-client" outside apps

[magos]

I am detailed to find a web site monitoring utility that will monitor up-time, page is necessary and also, to login and check integrity of the site.

Any ideas?

Also, this has to be something that I "install" on a centralized machine - in-house. I've ran across a ton of outsite services that will monitor your site from afar...

Thanks in advance...

[caine]

what about your web servers clock, usually quite good. other than that, you are probably correct there is tons of outside agencies that will drill in once and a will to see the site is up.