Skype dropped a bomb announcing that it's SkypeOut option will be offered for free for calls to landline or mobile phone in the U.S. or Canada, through the end of the year. The current rate is 2 cents/min.
All dialed numbers must be valid U.S. or Canada numbers and the caller must be calling from the U.S. or Canada (regardless of where your account is set up). The offer doesn't apply for callers overseas using Skype to call U.S. and Canada.
Skype has been feeling the heat from popular services from Vonage, Broadvoice and alike. They all let you make unlimited free calls to U.S. and Canadian numbers but for a monthly fee ($15-$40/month) but none are free like the latest from Skype.
Two trends are evident from the latest moves from Skype: VoIP rates are continuously falling as new companies enter the market (Microsoft, VoipDiscount and others); Skype's American owners from eBay want a bigger chunk of the American market since Skype has been extremely popular worldwide but somewhat behind in the U.S. and Canada with it's per-minute offering, inferior to unlimited options from Vonage and alike.