iCall Free VoIP
iCall lets you make and receive free or low cost phone calls on your Mac, PC computer, iPhone, or iPod Touch.
http://www.icall.com/

Free Skype internet calls and cheap calls to phones online - Skype
Make internet calls for free with Skype. Call friends and family on any phone with Pay As You Go and Pay Monthly subscriptions, sign up today at Skype.com.
http://www.skype.com/

5 Ways to Make Free Internet Phone Calls
Most of the free phone call applications I list below are PC to phone programs, meaning you can make a free call from your computer to a real telephone number .
http://freebies.about.com/od/computerfreebies/tp/free-internet-phone-calls.htm



Make and receive calls in Gmail | Google Voice Blog
Aug 25, 2010 . Google Voice lets you manage all your phone communications and . Wouldn't it be great if you could use your computer to make or receive calls? . To make a call, just click the Call phone link in Gmail and enter any number .
http://googlevoiceblog.blogspot.com/2010/08/make-and-receive-calls-in-gmail.html

Yahoo! Voice - Make Free and Low Cost Calls From Your PC
Make free PC-to-PC calls worldwide and call regular and mobile phones for as low as 1 a minute. Get a Phone In number to receive calls on your PC.
http://voice.yahoo.com/

PC to Phone Calls From Rebtel
Do you want to make phone calls straight from your computer? Tired of paying Skype's expensive connection fees? Check out Rebtel's PC to Phone calls!
http://www.rebtel.com/en/Services/pc-to-phone-calls/