Google's Near Field Communications payment solution Google Wallet has officially launched to the public.

The phone-based digital wallet NFC technology has been extensively tested and is now ready for a more mainstream trial.

Google is only making the Google Wallet app available to Nexus S 4G customers on the Sprint network in the US, so it's still a pretty small sample that are able to use the service.

The app stores your credit card details then allows you to pay for goods or cash-in coupons at stores which are geared-up with NFC reader devices, just by flashing your phone at the sensor.

International hints

Initially the service will be marketed in the US only for users of the CitiBank Mastercard and through Google Prepaid cards which can be topped-up using any credit card.

However, the Guardian is reporting that the pre-paid cards can be used at internationally at Mastercard PayPass reader-equipped stores in the UK like Boots, Burger King and Tesco.

At the time of writing, it hasn't yet been confirmed exactly what that means for UK Android owners as the app is only currently advertised for the 4G Sprint version of the Nexus S, not the UK device.

As Mastercard's PayPass service is available in the UK, a launch on these shores is possible in the near future, but there's no official information on the Google Wallet website.

UPDATE: And now Visa has jumped into bed with the big G too - meaning it's now both Mastercard and Visa's PayWave system that people in the US can use to pay for things using their phone.

"This agreement extends Google Wallet to Visa account holders worldwide," said Stephanie Tilenius, vice president of Commerce and Payments at Google.

"This is a crucial step towards realizing our shared vision for the future of mobile commerce – one that creates a rich shopping experience for consumers and merchants alike."

NFC 'tap and pay' tech and the Google Wallet service will be coming to more Android phones as the roll-out continues. Maybe the UK will get some love with the next Nexus handset?

Via Google, Guardian