Nexus S 4G owners, you may want to check your beloved handset for an update notification, because today Google announced that it's launching Google Wallet and that an update is now rolling out to NS4G-ers everywhere to enable the functionality. The update is build number GWK74 and, along with the new Wallet app, it also some unnamed Google security fixes. If you're not one of the lucky folks that have already gotten the new software, just stay calm and sit tight, as it'll likely take a little time to roll out to everyone.

As for Google Wallet itself, the new service is officially going live today, just barely making it in the summer timeframe that Google promised earlier this year. The service allows folks to use their Citi MasterCards or Google Prepaid Cards (which can be loaded up with any credit card) to pay for goods and services by tapping a near field communications-enabled phone on a MasterCard PayPass station. Anyone that sets up Google Wallet sometime between today and the end of the year will be given a free $10 Google Prepaid Card for being an early adopter. Google Wallet is currently only available to owners of the Nexus S 4G, although the functionality is expected to hit other NFC-capable phones later on. Finally, Google announced today that they're working with Visa, American Express, and Discover so that their cards may be enabled in Google Wallet in the future. If you'd like to check out a video of Google Wallet in action, mosey on down to the clip below.

Although NFC technology is nothing new, it hasn't really been able to gain any kind of traction with users yet. That may finally change soon, though, not only due to the introduction of Google Wallet but also because other manufacturers are beginning to include NFC chips in their handsets for making mobile payments. As for right now, it's kind of a bummer that only Nexus S 4G owners are able to take advantage of Google Wallet, but I'm sure the folks in Mountain View will be eager to roll the service out to others as more NFC-enabled devices hit the market. If any of you Nexus S 4G users out there get to take Google Wallet for a spin, let us know how it works for you!

UPDATE: Sprint's press release announcing Google Wallet is available below.

Sprint Launches First Google Wallet
Nexus S 4G is the first smartphone with Google Wallet; users can now make their phones their wallet and make purchases with a single tap using NFC

OVERLAND PARK, Kan. (BUSINESS WIRE), September 19, 2011 - Sprint (NYSE: S) and Google (NASDAQ: GOOG) today announced the rollout of Google Wallet to all Nexus S 4G customers – an app that enables consumers to transform their phones into their wallets and make purchases with a simple tap. Sprint is the first carrier and Nexus S 4G is the first phone in the United States to deliver this convenient, innovative service that lets shoppers tap-to-pay at hundreds of thousands of participating retailers, including American Eagle Outfitters, the Container Store, Macy’s, Foot Locker and Subway.

“Sprint is thrilled to be the first U.S. carrier to offer Google Wallet,” said Fared Adib, vice president of Product at Sprint. “Nexus S 4G is the first to receive new versions of Android software, and today’s upgrade puts the near-field communications, or NFC, chip in the phone to work so customers can have a secure virtual wallet on their phone. NFC capabilities on smartphones open the door to a new level of convenience and security.”

Google Wallet is a free Android app that stores virtual versions of a customer’s credit cards, offers and loyalty cards right on the one device they always have with them – their phone. At launch today, Google Wallet supports Citi® MasterCard® credit cards and the Google Prepaid MasterCard, powered by First Data. Google plans to support additional cards.

Google Wallet is designed to enable safe, secure payments. It requires users to set up a Google Wallet PIN that must be entered before making a purchase to prevent unauthorized access and payments.

“Shipping Google Wallet to Sprint is a crucial first step in creating a new way for people to use their phones to make shopping faster and easier,” said Osama Bedier, vice president of Payments at Google. “The world is on the brink of the next big shift in payments, and today’s announcement demonstrates that we’re making real progress in attaining the vision we share with our partners for a new and innovative mobile payments platform. We believe this is just the beginning of a transformation that’s soon to come.”

To find a participating merchant, customers can use MasterCard’s PayPass locator app for Android or visit http://www.google.com/wallet/where-it-works.html.

How to Get Google Wallet

Eligible Sprint Nexus S 4G customers will be prompted to download the latest version of Android software. Once this download is complete, customers can launch the Wallet app to try it.

Nexus S 4G from Sprint

Featuring the blazing speeds of Sprint 4G and a pure Google experience with Android™ 2.3, Gingerbread, Nexus S 4G is available today in Sprint stores and through www.Sprint.com for $49.99 with eligible upgrade or new two-year contract and after a $50 mail-in rebate via reward card1 (pricing excludes taxes). Nexus S 4G requires activation on one of the Sprint Everything Data plans plus a required $10 Premium Data add-on charge for smartphones. Sprint’s Everything Data plan with Any Mobile, AnytimeSM includes unlimited Web, texting and calling to and from any mobile in America while on the Sprint Network, starting at just $69.99 per month plus required $10 Premium Data add-on charge (pricing excludes taxes and surcharges).

About Sprint Nextel

Sprint Nextel offers a comprehensive range of wireless and wireline communications services bringing the freedom of mobility to consumers, businesses and government users. Sprint Nextel served more than 52 million customers at the end of 2Q 2011 and is widely recognized for developing, engineering and deploying innovative technologies, including the first wireless 4G service from a national carrier in the United States; offering industry-leading mobile data services, leading prepaid brands including Virgin Mobile USA, Boost Mobile, and Assurance Wireless; instant national and international push-to-talk capabilities; and a global Tier 1 Internet backbone. Newsweek ranked Sprint No. 6 in its 2010 Green Rankings, listing it as one of the nation’s greenest companies, the highest of any telecommunications company. You can learn more and visit Sprint at www.sprint.com or www.facebook.com/sprint and www.twitter.com/sprint.

1 The American Express Prepaid Reward Card (“Card”) provided in connection with this Rebate offer is a prepaid Card that is usable at U.S. merchants that accept American Express Card. Some limitations apply. The Card is not redeemable for cash (except where required by law) and does not provide ATM access. Use of Card constitutes acknowledgement that it is given as a reward and no consideration, value, or money has been paid by the holder to American Express in exchange for this Card. USE OF CARD IS SUBJECT TO THE CARDHOLDER AGREEMENT. SUBJECT TO APPLICABLE LAW, A $3.00 MONTHLY FEE WILL BE ASSESED AGAINST CARD BALANCE, STARTING SIX MONTHS AFTER CARD ISSUANCE, UNLESS FUNDS ARE EARLIER DEPLETED. For BALANCE, customer service and Cardholder Agreement, visit americanexpress.com/sprint or call 866-608-3756. Card issued by American Express Prepaid Card Management Corporation.

Via Engadget, Samsung, The Official Google Blog