Sprint just had another Tweet which not-so-cryptically reads:
"If you could design a brand new phone, what would it have? Ours will have a hub for gaming, music, pictures and video."
That's only one OS in the world and it ain't Android, baby! (Although technically, Samsung has been swiping "hubs" for their Galaxy SII phones...) We imagine in the next 48hrs a ton of info should be coming out regarding availability, pricing, etc. All we know is we can't wait and we'll be the first to order.
Finally, Windows Phone on CDMA.
Source: @sprint; Thanks, @bdattilo, for the heads up!