Looks like the CRTC in Canada may finally do something about this or at least they are having a hearing about this coming up. Its about bloody time.

Of course, Bell Canada could take some measures to thwart this pretty easily. They could have an option allowing me to set that I do not want to receive voice messages from people who don't actually ring through the phone number. I don't need anyone leaving me a message without trying to call me. Just make this an option and along with call blocking this is pretty much the end of it. Unfortunately that would require people with clues working at the phone company.

Also, the article mentions Infolink Communications Ltd but I've had voice messages from a number of companies.