Free calls and VoIP is tied together and you cannot break the bond between them and it doesn't seem possible in the distant future too. Here is another one and this is AllFreeCalls.net which enables U.S residents to make free calls to around thirty countries.

Its quite easy to use this service, no need for any software downloads and the phone at your home will do the trick. Just dial 712-858-8094 from your phone and for your ease the instructions are in Spanish and Mandarin too besides English. Now you need to enter 011 followed by the code of the country you wish to call and then the phone number. Though there is no charge but since you would be calling the access number based in Iowa, it will all depend upon your phone plan but generally it is free.

Here is the list of countries which you can call using AllFreeCalls

Argentina, Australia, Belgium, Brazil (Rio De Janerio), Canada, China, Christmas & Coco's Island, Cyprus, Denmark, France, Germany, Greece, Hungary, Ireland, Israel, Italy, Mexico, Netherlands, Norway, Poland (Warsaw), portugal, Russia, Singapore, South Korea, Spain, Sweden, Switzerland, Thailand, UK and USA.