This is run by netzero and it is absolutely free. You can even personalize your voice message. When people call your number they can leave a message. I have it so that should I receive a message I will get an email to notify me (or if you prefer, you can be notified on your cell phone). You also have a choice of different area codes.
This is perfect for those sites that require a phone number and you don't want to give out your home phone, or exes.
Just got mine in my own area code. really neat.