Software by S5 Development:

Monitoring The Web is a simple, effective and useful web based service that allows to monitor accessibility and functioning of internet resources like Web sites, VoIP and FTP servers. By using diagnostic requests via the protocols HTTP, FTP, PING, and SIP, this utility continuously monitors server responses. If the server responds abnormally, a warning message with a brief description of the problem will be emailed to service support.

"Linking The Web" is a free utility that regularly monitors all backlinks to your sites. If some of the links don't exist, contain wrong anchor, are covered by a "nofollow" flag or hidden by robots.txt then you will be immediately notified by email. Also the program can keep track of your purchased links and notify you about their expiration dates. The software is free of charge and works under all versions of Microsoft Windows.