connectivity

My company has alot of affiliates and we support their networks remotely; Many of the issues are connectivity-related.
I would like to install a program for the computers on these networks that will automatically ping out, say every five minutes, then at the end of the day will send such reports to my email. This way I can be notified that company A was down from 2-4, company B was up and running all day, so on and so on. I am looking for such a program with as little user intervention as possible.
Any answers?