(UPDATED) Sources familiar with plans say the much rumored Google mobile payment product using near field communication (NFC) technologies will finally be announced this week. Bloomberg is reporting that Google will announce on Thursday that it is partnering with wireless carrier Sprint Nextel Corp. in the effort.

Google's Nexus S phone, which supports NFC technologies, is currently available through Sprint and T-Mobile USA.

The Bloomberg story does not include any information on the financial partners in the venture. A source familiar with the plans confirmed to Mobile Payments Today that Google is working with MasterCard Worldwide to provide the platform to process NFC payments. Additionally, the source said that Citigroup Inc. is involved in issuing the mobile MasterCard accounts.

The Wall Street Journal reported in March that Google was in talks with MasterCard and Citi. The Journal is reporting today that retailers like Macy's Inc. and the fast food chain Subway are participating in the initial trials of the NFC payment method. Participating merchants will reportedly be able to process contactless payments as well as be able to access customer data to provide targeted coupons and offers.  

According to Bloomberg, Google is reportedly looking to launch NFC payment services in New York, San Francisco, Los Angeles, Chicago and Washington D.C. The timetable for implementing the program will be announced on Thursday as well.

More to come as information becomes available. 

Update: Correction to statement about Nexus S availability. It is available through both Sprint and T-Mobile.