RJA,
NexBoom offers VOIP for residential homes. You can purchase the service for yourself and one for your parents. Send it to them and you both can call each other FREE and unlimited calling to US & CAN. All it requires is broadband connection and the IAD/Router you get from NexBoom. I love mine and I bought one for my parents for Christmas. We call each other all the time plus they get to call other family members and family all across US. Your NexBoom router has a phone jack in the back and uses a regular corded/cordless phone. http://www.voip-boom.com Good Luck! Hope this helps!!