Google Wallet, a mobile payment system on Android-based Sprint smartphones, is expected to be unveiled at a media event in Google's New York office, at 12 p.m. today.

The unveiling of Google Wallet was leaked from a retailer's memo stating, this summer Google will launch a test of 'contactless' payment through a mobile device - so customers will be able to just tap a special device and pay with their phone in stores. The memo continues to say that all the participating retailers will be announced at Thursday's event.

Google Wallet is expected to tap near-field communications technology (NFC), allowing the devices to exchange information wirelessly with one another up to a distance of 4 inches.

The event is scheduled to be held at Google's New York offices. It will kick off at 12 p.m. ET.

Partnering with MasterCard and Citigroup, Google Wallet will be available for debit and credit card users, of MasterCard and Citigroup, to pay for retail purchase using the NFC-equipped Android smartphones.

Rumored retailers to take part in Google Wallet are Macy's and American Eagle. The service is reportedly to be tested first in New York, San Francisco, Los Angeles, Chicago and Washington, D.C.