Automated Web server monitoring

[Reference Librarian]

Is there an automated method for gathering data on Web site downtime or
"busy signals?" We're searching for a way to know if our Web site becomes
unavailable while we're not looking, whether through an unplanned outage or
through inadequate server capability, and whether our site is hosted on our
own network or by an outside provider. Please send pointers to products, Web
sites, articles you've found helpful, and I can summarize to the list.

Thanks,

Melissa J. Brenneman
Reference Librarian
Knox County Public Library System
500 West Church
Knoxville, TN  37902                            865-215-8723