Auto dialer software needed

Hi all, im setting up a network pro bono for a local non-profit youth center. The administrator asked me about auto dialers.

What he is looking for is something that will call a supplied list using voip, play a pre-recorded message and hopefully give the listener a few options, like press 1 to hear this message again or press 2 to leave a message.

This is their primary way of sending notices to parents and youth regarding events and for fund raising but they have a hard time finding warm bodies to physically make the calls.

I've seen a few, including IVM answering attendant ( http://www.nch.com.au/ivm/index.html ).
The cost was a bit prohibitive but could handled, I downloaded the trial version and it worked great, on my at&t dsl line. when i was at the center i went to show him how it worked, and the thing wont work with his internet service, charter highspeed.

so the question is, does any one know of auto dialer software, open source or cheap.

i will set up asterisk or 3cx for them if need be.

Any help appreciated guys. thanks.