Sending a sound file down a phone line

Does anyone know how to send a sound file/media stream down a phone line? I have to dial a mobile phone in the event part of the system crashes and I would like to play some kind of sound file to the person who answers the phone to tell them why the system is calling them.

eg: Internet connection crashes on an ISP should play some kind of file that says "Please restart your internet connection"

It would have been nice to do it with an sms but there are too many hasses with sms gateways and the like. Sound file is just as good, providing on of you geniuses can figure it out. :p