Many vendors can supply the software and services necessary to add VoIP to your mobile computer.
Here are some of the most well-known VoIP vendors, along with a general idea of their charges:
Essentially, the issues involved in adding VoIP to a mobile computer are the same as those involved in adding the capability to a desktop computer. In both cases, the computer needs to be connected via broadband to the Internet, whether via Wi-Fi to a hotspot, Wi-Fi through a private network, or via standard Ethernet cabling.
DeltaThree, http://www.deltathree.com, provides iConnectHere software and VoIP services with no-plan rates at about $.03 per minute worldwide (rates are lower with minimum purchase plans), and calls to other iConnectHere ...