I've been using Google's (NASDAQ:GOOG) GrandCentral service for a couple of years now, so it's good to see it finally coming out of its little shell. Rechristened as Google Voice, GrandCentral is about to simplify a whole lot of address books.

What does it do?
Simply put, Google Voice helps you manage your phone numbers. Sign up for the service and pick an area code. The phone number you get will then act as a central connection, forwarding the calls it receives to your home phone, cell phone, work number, and any other phone you might have.

It's easy to set up rules for what calls go where, and the service comes with handy extras like call recording and emailed voice mail transcripts. The last time I changed my landline provider, signing up for GrandCentral was an obvious choice.

Competition and competitive advantage
Now, the service isn't totally unique. My old Vonage (NYSE:VG) account could also forward calls to one or more cellphones. However, Google Voice puts a host of friendly extras at your fingertips for free, whether you send monthly checks to AT&T (NYSE:T), Verizon (NYSE:VZ), Vonage, or to Sprint Nextel (NYSE:S).

And if you ever change service providers, it only takes a couple of clicks to keep your Google Voice forwarding current. It's a hassle-free lifetime number -- assuming that Google stays in business forever.

Big G in the house
It's also a great example of how Google can leverage its experience from several semi-random experiments and cook up something better than the sum of the parts. The Google 411 service that made so little sense on its own has trained the voice recognition algorithms that fuel Google Voice's text transcripts. And once your call has been transcribed, you can find it with text-based searches, just like you would for Gmail messages. Sweet!

Nothing's stopping the phone companies or even Microsoft (NASDAQ:MSFT) from concocting their own equivalent of this Google service, of course. And it's not clear how Google intends to monetize Google Voice, if at all. What else is new? But this puppy has potential and a significant head start on the rest of the field. This is Google at its mercurial best, building great tools first and asking for money later. Why change a winning recipe?

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Fool contributor Anders Bylund owns shares in Google, but he holds no other position in any of the companies discussed here. You can check out Anders' holdings or a concise bio if you like, and The Motley Fool is investors writing for investors.