Google Wallet goes live with NFC payments

Google (s goog) is finally opening up its near field communication payment system, Google Wallet, today to the public, allowing Nexus S users on Sprint (s s) to try out contactless payments through their smartphone. It’s a little later than originally expected and again, with only one handset that supports it, Google Wallet is just the first step in a long process.

But it’s a significant one that begins a much broader effort by Google to change both the way people pay for goods in the real world and interact with merchants and retailers. Toward that end, Google announced today that it has struck deals with American Express (s axp), Visa (s v) and Discover (s dfs) so their cards will also be integrated into future versions of Google Wallet. Initially, Google Wallet launched with MasterCard as its first partner. But now, banks that issue cards through Visa and Discover will soon be able to load up their accounts directly on to Google Wallet.

For Google, the wallet initiative signals a new opportunity to market deals and discounts to consumers and allows merchants a new way to reach consumers and strengthen their relationships with them through discounts and loyalty programs. And it enables them to close the loop on transactions, so they can see how effective their marketing is.

That’s what Google is really interested in: Taking a slice of the revenue that comes from increased Google Offers that can be redeemed through Google Wallet. It’s also one reason why the search giant is not taking a cut of the transactions. Instead, Google is trying to exploit the big opportunity in local advertising, taking NFC along for the ride. As an early incentive, Google is throwing in a $10 credit for users to try out Google Wallet this year.

Google Wallet in tandem with Google Offers is going to be a big venture in a market that will be hotly contested. Isis, a rival NFC payment system led by AT&T (s t), Verizon (s vz) and T-Mobile is also preparing to launch early next year. I recently wrote about PayPal (s ebay) unveiling the first glimpse of its offline payment solution, which won’t leverage NFC. Square, a hot start-up, is also capitalizing on the opportunity with mobile card readers, an iPad(s aapl) cash register system and a digital wallet for consumers. The credit card companies themselves are also pushing their own digital wallet programs. This is going to be a crowded market and all these companies, along with a host of smaller competitors, are going to trying to make good on this opportunity in mobile payments.

Google Wallet, if you recall from the big unveil in May, is a joint venture with MasterCard (s ma), Citi (s c), Sprint and First Data. Users can connect their MasterCard Citibank cards to Google Wallet or load up funds on to a prepaid card in Google Wallet from other credit debit cards.

Users can make payments at any terminal equipped with MasterCard’s contactless PayPass technology. Google has struck a bunch of partnerships with retailers and restaurants, who will support Google Wallet and incorporate their own loyalty programs into it. In some of these cases, retailers need to work to enable or upgrade their point of sale systems to handle Google Wallet integration. Partners include Bloomingdale’s, Macy’s, Walgreens (s wag), Subway, American Eagle Outfitters (s aeo), Peet’s and others.

There’s still many questions around Google Wallet. Google said it’s talking to other carriers and manufacturers about supporting Google Wallet and including NFC integration, but right now, there are no other Google Wallet handsets to announce. It’s also unclear when other bank cards will be supported directly in Google Wallet though Google said it is talking to banks about adding that functionality. But Google has pitched its wallet as an open platform that anyone can participate in, so the system will no doubt evolve over time.

Google still has a long ways to go to pitch consumers on the benefits of paying by phone. As we’ve noted, many consumers are happy paying with a card. Merchants also need to see a reason to step up and make an investment in next generation hardware that can support contactless payments. This is going to take a lot of selling and a good narrative for both parties. Google hasn’t embraced big marketing campaigns in the past though it has enlisted the help of actor Jason Alexander of Seinfeld fame to help tease Google Wallet. It’s going to need a lot more of that mojo to make sure Google Wallet can realize the company’s ambitions.