>I have a program (VFP9) running on a custom computer 24/7. It is very important for the customer that the program never stops or that someone is alerted if it stops. But sometimes, for whatever reasons, it will hang. Is there a way to monitor the program from a Windows service or whatever other way?

We have the same issue with some of our programs - they MUST run 24/7.
Other failure modes are important too.
--The power could go out.
--The computer could fail.

You need to have an offsite computer monitor that the first computer is doing its work.
A failed computer cannot notify you of anything.

I would suggest having the working computer contact a web server every minute.
Then have script on that web server that will send alerts if it does not hear from the work computer in 5 minutes or so.
You can send SMS to your phone easily via your cell phone providers sms gateway http://en.wikipedia.org/wiki/List_of_SMS_gateways

You can get web hosting very cheaply, and there is a lot of sample PHP code available.

Good Luck!