This is not a hot deal for everyone but if you want to save a couple hundred a year there is a program that you can use to notify you of all incoming phone calls while online. I have tried it and it works quite well and also had caller ID with it. It is $50 a year which was two months bill for me for the extra phone line.
http://https://www.internetcallmanager.com/
http://https://www.internetcallmanager.com/