A fun story re the, allegedly legal, blocking of competing services by several   telcos ( stupid spellchecker changed that to  tax shows...

AT&T/Cingular, Sprint and Qwest Collude to Kill FreeConference | Guidewire Group

Earlier this week, Sprint and Qwest joined in this action, blocking cellular and land line calls to these same numbers. This appears to be a coordinated effort to force you to use the paid services they provide, eliminating competition and blocking your right to use the conferencing services that work best for you.

Seemingly paying a phone company to provide service in the USA is merely a courtesy they extend to you, it's not like they -have- to give you a working network, with timely message delivery and should the call actually work it had better be to our approved list of numbers and services.   Not that big a step to apply this to their internet services too as they charge by the mime type per  meme type making it very difficult to buy a device/ service that can utilize it's capabilities without needing a slough of add ons. To see this encroaching into the area of voice calls is rather amusing  but doesn't bode well for any "disruptive" services that affect their bottom line.