Google Voice: 5 Reasons to Use it, 5 Reasons to Think Twice
Google Begins Sending out Google Voice Invites

In a nutshell, Google Voice a front-end for all of your phones. It assigns you a new phone number which you can then use as your primary number. You then get to decide who gets routed to which of your phones, either individually or by using groups. Next, you can personalize voicemail greetings depending on the caller.

Say you're going to visit some relatives who live out to the boonies. Unfortunately, you are way out of cell range and expecting an important business call, or you need to be reachable in case of an emergency.

Traditionally, you would need to inform the calling party of your relatives' phone number. With Google Voice, you simply create an entry with your relatives' digits and specify which groups or individuals will automatically be routed to the new number. You can now relax knowing that you are reachable in case of an emergency, and your paranoid uncle can be assured that you didn't advertise his number to your questionable friends.

Let's say you meet someone at a party, and finding no good way of blowing them off, you reluctantly exchange numbers. You could set up Google Voice so that when they call, they're immediately directed to a voice mailbox with a greeting that's been personalized to say, "You seemed very nice, but I'm spineless and have no interest in dating you".

Frankly, I find checking voicemail to be mildly inconvenient. It may be because of my ADD, or perhaps my tendency to find myself in noisy environments, but I'd rather to get messages in ASCII than in audio. Not everyone in my life feels the same way I do, so I get a fair number of voicemail messages.

Google Voice can transcribe an incoming voicemail message and either e-mail or text it to you. This is fantastic for messages of your long-winded mother in law, or from colleagues you can't stand, because it lets you skim the text for important details without having to sit there listening to rambling chatter. Unfortunately, the technology isn't quite ripe yet. Instead of "meet me at Lanesplitter Pizza on San Pablo at University", you might get "meet me at lame spitter Pisa on some pebble adversity". Google acknowledges the limitations of this technology and claims to be improving it.