Coming soon...Google Voice.
Basically, Google purchased a company called GrandCentral a while back. GrandCentral provided a service that allowed people to have one phone number associated with a bunch of phone lines. There are many neat applications to this technology.
So, for example, let's say I have both a cell phone and a home phone. Using this service, I could set it up so if someone called my cell phone, both my home and cell phone would ring.
Looking at this another way, if I had a small company and wanted to have a few people doing technical support, I could set it up so that between midnight and 6 am, all calls get routed to one person, from 6 am to noon all the calls get routed to another, etc.
Or, let's say I have a small company, and I want to provide customers one phone number. I could create one number for the company, and then set it up so that it rings all of my customer service representatives, and whoever picks it up, gets it.
This is basically the way telemarketing companies work, except now you can use that for your own purposes, be they personal or professional.
Google saw how cool this is and purchased the company, and they've been working on this for the last few years. They announced in March that coming "soon", this service will be available to the public for FREE.
There are other features as well, including blocking numbers and personalizing what happens when certain people call.
There's a lot of potential here. I personally have three phone numbers (land line, cell phone, work phone), and I get no cell phone reception in my apartment. When people call my cell phone at the moment, I have to call them back from my land line while in my apartment. It would be so nice just to pick up the house phone rather than the cell phone.
Google Voice information
New York Times article