With Google Voice, there is no hardware to purchase and no new telephone equipment required. You can use it with or without a computer. The voice calls are never sent to your computer so you don't have to wear headphones or anything like that. You simply use the normal telephone(s) you already have.
Google Voice is now out of the limited, invitation-only beta test and is available to anyone in the US.
My friends and relatives no longer have to "hunt me down" by calling a series of different numbers hoping to find where I am. They simply call my one new telephone number and I can answer on the ringing telephone that is near me, often my cell phone.
If I am not near any of the ringing telephones, the call goes to voice mail and is recorded, and then a computer-generated transcription of the message, along with an MP3 recording of the same message, is sent to my email address. I have received voice mail messages this way when I was traveling in New Zealand, England, and elsewhere.
In addition, anyone in the US can call me free of charge, if they click on the "Call Me" icon at http://blog.eogn.com/eastmans_online_genealogy//contact-us.html
Not bad for a free service! (Calls placed to overseas telephones do cost two cents a minute or more, far cheaper than what the local telephone company charges. Calls to the US and Canadian telephones are always free of charge.)
Google Voice requires that a new telephone number be assigned to you. There is no capability to transfer existing telephone numbers. Telephone numbers may not be available in your home town; you may have to accept a number that is normally assigned to some other town a few miles away.
In my case, I selected a Utah telephone number, even though I live on the east coast. I receive a lot of calls from Utah businesses and residents, so I thought that having a Utah number would be convenient for them. Admittedly, it does confuse some people when I tell them of my 801 area code. It's usually good for a laugh and a short explanation.
With Google Voice, you have a choice: you can obtain a local telephone number that is probably within a few miles of your residence or you can obtain a number from a distant area code, if that is more convenient for your friends and relatives. Do you live part of the year in a winter home somewhere in the sun belt? If so, you can obtain a local number from "back home" and receive calls in your winter home at no charge to you or to the callers. Your friends back home will be placing local calls to a number near them but that number rings in your winter home, your summer home, and on your cell phone, all simultaneously.
For more information, or to sign up for this FREE service, go to http://voice.google.com