Google is doing to phone service what they did with Gmail to email service. Now (Invite only of course at this stage) you can add Google Voice to your phone to be able to do the following:
Is this cool or what? DO you want to make it even more cool? Add a Google number. You get a Google number that stays with you no matter where you go, you just go online and link other numbers to it, so if you home number changes, you can change it, if your cell changes, you can change that, and no one will know you have changed numbers, because our google number stays the same-Forever!! There are other added features that I will discuss later with Google number.
These are still invite only services so it might take some time for you to be able to use it on your phone. But in the meantime I have Vonage, and I’m able to do most of these now (I’ve been doing them for 3 years actually) but it’s on the land line.