Skype.com is offing Unlimited calls from your computer to the US and Canada for $14.95 a year thru Jan 31st


Unlimited Calling gives you a full year of unlimited calls to anyone, on any phone, within the US and Canada for just $14.95.($29.95 after January 31st 2007)


With the unlimited you get:

* 12 months of unlimited calls to any phone in the US and Canada - right from your computer.
* More than an hour of international calls*.
* Over $50 in coupons to get a Motorola headset, Netgear WiFi phone, and a Polycom speakerphone.

Now this is what I would do
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*Load skype on all your computers
*If you have a Windows Mobile/ Pocket Pc pda with wifi or Smartphone with internet access you can install the Skype Mobile client and make calls. You would probably want to have unlimited data or use a wifi access point.
*Get a Skype Gateway or Cordless Skype Phone

*The cordless Skype Phone speaks for itself
*A Skype Gateway http://www.voip-info.org/wiki-Skype+Gateways connects your regular phones to a skype adapter and you can make skype calls from any phone in your house. Two things to note.
1. You'll need a computer that is always on and connected to the Internet to use this effectively. The skype gateway is a usb device that plugs into your pc running skype. Skype runs on Windows, Mac OSX, Linux. This is the only skype adapter that I know of that has software available for all the Operating Systems http://www.echostore.com/skype-phone-adaptor-usb.html So dust off that old computer, stick a USB wifi dongle or connect it to your router and run it without a monitor in a closet or out of sight when you have it setup.
2.You may need to rewire your phones if you want all your phones to be able to do this. If you have VOIP Phone service in theory, you should be able to attach a device like this before it connects into your Voip adapter. It's really easy for me, all my phones are wired to distribution panel and I can add and take away lines at will. When I switched from Bellsouth I literally unplugged one line and connected the other from my voip adapter in two clicks. Below are a few sites that can show you how to do it

http://www.engadget.com/2006/06/20/how-to-wiring-voip-to-your-phone-jacks/
http://www.jakeludington.com/ask_jake/20050206_voip_over_phone_wiring.html
http://michigantelephone.mi.org/distribute.html