The idea of waving your phone around to pay for something may come one step closer to widespread, in-the-U.S. reality this summer thanks to Google. Rumors indicate the search giant intends to test a mobile payment service in New York and San Francisco.

If true, this move would represent a sort of natural advance for the company. Google already made sure that Gingerbread and the Nexus S support near field communication (NFC) tech, even though there are few opportunities for users to take advantage of it right now.

Plus, Google’s tested NFC in conjunction with Hotpot in Portland.

So here’s the original story: Bloomberg reported this morning, “Google Inc. (GOOG) plans to start testing a mobile-payment service at stores in New York and San Francisco within four months, letting shoppers use their phones to ring up purchases, two people familiar with the project said.”

Then the Bloomberg article continued, “The company will pay for installation of thousands of special cash-register systems from VeriFone Systems Inc. (PAY) at merchant locations, said one of the people, who requested anonymity because Google’s plans haven’t been made public.”

In somewhat related news, we heard last week that Groupon – which Google supposedly tried to buy for $6 billion – is researching special cash registers, as well.