SkypeOut, which allows you to dial real phone numbers from your own computer (as opposed to just PC to PC), is free to any number in the U.S. or Canada until the end of the year. The service typically costs 2 cents a minute within the U.S.
From the email:
Starting from today it doesn’t matter if it’s a Skype-to-Skype call or a call to landline or mobile phone – it’s free as long as you’re calling from within the US or Canada to US or Canadian phone number.
– via MyMoneyBlog.com