Many people may not know about Magic Jack. It is a small dongle that plugs into a usb port and provides unlimited telephone service. You can buy the device and 5 years of phone service for $110.00. I won't provide a link to it because somebody might think I'm trying to earn a commission selling the service. You don't need a link anyway because you can find it easily by doing a search for in on google or any search engine. You can use it from your computer screen and a headset/microphone unit but dialing out is a pain. But you can use any cordless phone and everything works just fine. You can plug the magic jack into any phone jack in your house and it will power all the phones in your home. Radio Shack makes a great telephone to go with it. The Radio Shack phone looks much like a Blackberry and works well with the Magic Jack. It is a bit expensive, costing $100. If you get their 2 year warranty it comes to $130. The phone also connects to Microsoft MSN Messenger so if you have people you talk to using MSN you can do voice direct using the phone. On the other hand, you can just use any cordless phone. Magic Jack comes with unlimited long distance, call waiting, call forwarding, conference calling, caller I.D. and just about anything else the regular land line phones such as AT&T has and charges high monthly rates for. The only limitation is that you must have cable or DSL. Regular land line connections won't work. I also have AT&T but once I got Magic Jack working I canceled all the extras on that line and only use it for receiving faxes. I'm thinking about buying a second Magic Jack as a fax line and getting rid of AT&T all together. AT&T is far too expensive and doesn't give any better service than Magic Jack does. I put mine on a separate computer. I went to a store that sells old computers and got one for $20. I put a small 80 gig hard drive in it that I had laying around. I put 512 megs of ram in it and an old CD rom I got for $5 at the same store. I also bought a flat screen monitor I found on Craig's list for $50 that someone was selling. So when I got done I have very little invested. I also installed a program called phone tray that announces who is calling and puts their caller ID on the screen. It lets me zap the calls from telemarketers, out of area, N/A calls, or any others I don't want to hear from. I think that program cost me $16 and you can find that by searching for it too.
Vonage (Vonage - VoIP Internet Phone Service for Home, Business and International Calling: Vonage - A Better Way to Phone for Less) has worked well for us. The good news is that it's not connected to a computer, but the bad news is that it's not connected to a computer. I personally like the fact that it doesn't require a computer but Cap1Sucks' idea of getting a cheap-o computer isn't bad.
I have vonage too and I like it a lot but it does have one disadvantage. It must be connected to the internet at all times or their call forwarding don't even work. It isn't that way with magic jack. I have both vonage and magic jack on call forwarding to my cellphone. I could take magic jack to the public library or a friend's house and plug it into their computer and it would let me make calls and of course I would receive incoming calls on my cellphone and could make outgoing calls with my cellphone even if I was nowhere near a computer. Vonage has to be live on the internet at all times. If it isn't then call forwarding don't work either. So there are some issues with either one. Neither is perfect but then lots of things aren't. If you are in a storm and all you have is a land line such as AT&T that connection can go down on you too. If you have only a cordless phone and a land line and are hit with a severe storm and your home loses power your phone will only last until the batteries run down on the cordless phone.A good set of UPS battery backups will keep you on for a while but not forever. That's something most of us never think about. What happens if an ice storm or a hurricane or a tornado rips out your power for maybe a week? I had that happen several years ago. I had a huge back up power system but even that was about to go out when they finally got power back on. Shortly after that I went out and bought a good generator. Now I have several UPS boxes plus the generator.