They make a cron daemon for windows I'm sure. For unix I use Mond .. it does this and more ... all using SMNP unless otherwise specified. Checksa out my printer to make sure I've got toner, paper jams, etc. Examines my router for proper responses. Checks my available disk space on a variety of machines. Looks for processes that take up too much cpu or time (stuck), check the web site, email, and ftp servers for real responses not just pings.

And this is just what I use it for, it's got the capability for so much more. It'll even page you, email you, or phone you if you've got a modem. Crazy.

Greg