For years it's been Apple (Nasdaq: AAPL) putting rivals on the defensive with simple-to-use tech in its iOS devices. No longer. Google (Nasdaq: GOOG) has the lead now.

Yesterday, the Big G made good on a promise to launch its Google Wallet pay-by-smartphone service before the end of the summer. Apple has been rumored to be working on something similar for its next-generation iPhone, but it's Google that is working with American Express (NYSE: AXP), Discover Financial (NYSE: DFS), and Visa (NYSE: V), as well as initial partners Citigroup (NYSE: C) and MasterCard (NYSE: MA). Talk about a coup.

To be fair, first-mover advantage has never been Apple's strong suit. The Mac maker typically waits, observes, and then introduces tech that leapfrogs the existing paradigm in terms of usability. Think of iTunes. While existing paradigms for downloading music existed before it came to be, it was Apple that created a piece of partnering hardware (i.e., the iPod) and convinced labels to sell individual tracks for $0.99 apiece. Apple's simple strategy has proved to be incredibly effective.

Simplicity matters here, as well. But partners might matter more. After all, Google Wallet is nothing more than software that wirelessly connects a near-field communications (NFC) chip inside an Android phone with a payments terminal. Neither device means much without the ability to process payments through a major credit or debit service. Google has now solved that problem.

And while Apple hasn't said anything in this area, it wouldn't be difficult for the Mac maker to create its own payments system. Indeed, it already has one: iTunes. I've used iTunes credit this way -- mostly for buying digital comics through services such as comiXology.

There are also the times I've used iTunes to pay for movie rentals, TV-show downloads, and music tracks. My son has used iTunes for in-game purchases, validating Zynga's well-publicized social-gaming business model. What prevents Apple from making iTunes an even more prolific payments processor? Answer: nothing.

Imagine your iPhone connecting to an iTunes terminal located near the register at your favorite spot in the mall. Your purchase gets processed through your iTunes account, which is connected to a major credit card issuer. No additional partnerships required.

Seem far-fetched? Maybe, but having an iTunes payments terminal would also bulk up demand for iTunes gift cards, boosting Apple's apparently supernatural ability to generate cash.

But that's what could be. Google Wallet is already here, is available on Samsung's Nexus S, and is compatible with all five of the major credit and debit card issuers. It's your move, Apple. Make it a good one.

Do you believe the next iPhone will include a service like Google Wallet? Would you want a service like that? Please weigh in using the comments box below. You can also keep track on developments in digital payments by adding any of these stocks to your Foolish watchlist.

Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He owned shares of Apple and Google at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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