Google announced Google Wallet today. It’s an app aimed at turning your phone into your wallet. That’s exactly how Google puts it.

More specifically, it lets you store credit cards, coupons, loyalty, and gift cards on your phone. Google says it does so securely. The app uses near field communication (NFC) to let users tap to pay.

“A key benefit to retailers will be the integration of coupons, or offers, into Google Wallet. We’ve been testing a variety of offers – from discounts directly within search ads to check-in offers to offers in Google Places,” explains Google Director of Commerce Partnerships, Spencer Spinnell. “Over time, consumers will be able to save each of these offers directly to their Google Wallet. That means consumers will get the benefit of carrying their offers with them at all times, bringing retailers targeted foot traffic.”

Speaking of commerce partnerships, the company has partnered with Citi, MasterCard, First Data, and Sprint. At first, it will support both Citi MasterCard and a Google Prepaid card (which Google says you’ll be able to fund with about any payment card). “From the outset, you’ll be able to tap your phone to pay wherever MasterCard PayPass is accepted. Google Wallet will also sync your Google Offers, which you’ll be able to redeem via NFC at participating SingleTap merchants, or by showing the barcode as you check out,” the company says. “Many merchants are working to integrate their offers and loyalty programs with Google Wallet.”

While it may start with payments, Google apparently really does want to take over your wallet as a whole. Aspirations are much more ambitious than just paying for stuff.

“Because Google Wallet is a mobile app, it will do more than a regular wallet ever could,” Google says. “You’ll be able to store your credit cards, offers, loyalty cards and gift cards, but without the bulk. When you tap to pay, your phone will also automatically redeem offers and earn loyalty points for you. Someday, even things like boarding passes, tickets, ID and keys could be stored in Google Wallet.”

Currently, Google Wallet is only in field test mode, but the company says it will be widely available this summer, though at first, it will only be compatible with the Nexus S 4G by Google (from Sprint), but they’ll be expanding to more phones in time. Google says it will be developing APIs to enable integration with numerous partners.