http://www.stanaphone.com/
StanaPhone is a free and simple internet telephone that uses a real US phone number and enables user to make and receive free calls to and from any phone anywhere in the US, Canada, and a selection of other countries. The software is free to download and free to use. It works with all PC headsets and USB internet phones providing the same or better sound quality than a regular household phone.
Free unlimited incoming calls from any phone & from anywhere
Free unlimited quantity of US numbers for any one anywhere
Free unlimited outgoing calls to other StanaPhone numbers
Free 100 minutes per month of outgoing calls to regular phones
Free calls to selected countries are included into 100 free minutes
Free to set up - download and start making calls immediately
Easy online account management for each StanaPhone number
Any PC headset & USB internet phone works with StanaPhone