Chances are you've heard or read about Google's phone management system Google Voice, but you're not really sure what it does. There's a good reason for this aura of mystery. Google Voice got its start as a phone service called GrandCentral, which the search giant bought in 2007. It's been in beta ever since -- but unlike other Google betas that are open to the general public, this one was limited to former GrandCentral users and a select group of industry elite.

But now Google is opening up the service to a limited number of new users, many of whom I'm sure will be as impressed as I am with Google Voice's power and elegance. Even better, Google Voice is free -- at least for now. It's likely that Google will need to monetize the service at some point, either via subscription fees, advertising, or some sort of newfangled revenue scheme. But for the lucky few using the service today, there's no charge.

The Basics

Google Voice provides a single phone number, such as 415-555-1212, for all your cell, home, and work numbers, and lets you manage your voice services online. Unlike a landline service, a Google Voice number isn't tied to a geographical location. Unlike a cellular service, it's not linked to a specific handset. And unlike a VoIP line, it's not matched with an IP address. Rather, it's tied to you. So if you move, change jobs, or switch wireless carriers, your Google Voice number stays with you. One drawback: you can't port your current number to Google Voice, although that option may be added in the near future, the company says.

This isn't a Skype-type service either. You don't use your computer to make phone calls, and there's no additional software or hardware to install or buy. (You can, however, use the Click2Call feature from the Google Voice website to place calls.) Is it perfect? No, it's got a few quirks, and the myriad of configuration options can be confusing at times. But Google's onto something big here. A service that helps manage the multiple phone lines in our lives should have universal appeal.

Google Voice provides a powerful suite of communications tools, including the ability to:

Forward calls from your Google Voice number to one or more phones, or directly to voicemail. Based on who's calling, you can select which of your phones will ring.

Receive text (SMS) alerts when you get a call.

Transcribe voicemails, which Google Voice will send as email and/or text messages to your cell phone.

Listen to voicemail messages as they're being recorded-a great throwback to the home answering achine.

Screen callers by asking for and recording their names.

Block annoying callers by playing a number-not-in-service recording when they call.

Vary personalized greetings by caller.

Record phone conversations and listen to them in your Google Voice inbox.

Switch phones during a call.

Use the free GOOG 411 service to say the name and location of a business, and have your call connected for free.

Phone U.S. numbers for free.

Getting Started

Since Google Voice is a browser-based service, you won't need to install software on your Mac or Windows PC (or mobile phone) to get started. Like most Google apps, Voice has a clean, no-frills interface that's easy to learn. The Settings page provides easy access to the rich set of phone tools.