The story first surfaced on The Information, a two year old paid subscription technology news site founded by ex-Wall Street Journal writer Jessica Lessin. It cites three un-named sources as saying the project, code named "Nova", is headed up by Google VP Nick Fox who has served as a Product Manager for both Android and Google Adwords.
The story has since been picked up by the Wall Street Journal, Time and dozens of tech news sites. So far Google, Sprint and T-Mobile have said nothing about the project so everything that has been written about it is speculation.
My take is that wireless from Google will likely be a low cost no-contract service that emphasizes data rather than voice. Google has experience delivering high speed public WiFi so I wouldn't be surprised if Google Wireless was a Wi-Fi first service like Republic Wireless that uses Wi-Fi for calls, messaging and data whenever possible with the cellular network as a backup when there's no Wi-Fi.
Many of Google's new products including Gmail, Play Music and Chrome OS, have launched as small scale beta tests that were expanded to general availability over several months or even years in the case of Gmail. It would make sense for Google to launch its wireless service first in its Google Fiber markets where it has a high speed network in place to serve the tens of thousands of WiFi access points needed for a robust Wi-Fi first network.
It's also possible that Google Wireless will not happen. There have been countless rumors of Google becoming a mobile operator of MVNO over the years starting even before Android launched. None of those rumors proved true and this one might not either. I hope it is true as I believe Google's entry has the potential give the US wireless industry a much needed shake up.