Skype is undercutting the competition with this announcement today:
Skype on Monday turned the Internet telephony industry on its head by introducing free calling to traditional landline and mobile phones in the United States and Canada through its SkypeOut feature. The move comes just days after Microsoft introduced Windows Live Messenger beta with its calling service.
SkypeOut previously charged users per-minute fees for making calls to non-PC users -- a business model being adopted by a number of rivals, including Yahoo, AOL and Microsoft. Now, Skype users can call both fellow Skype users and standard phone numbers without being charged until at least December 31, 2006.