Rafael Rivera of CheveronWP7 fame has tweeted that Sprint customers will be enjoying Windows Phone 7 in the first two weeks of March. And the phone of choice for Sprint shall be the HTC 7 Pro. This makes sense as we just saw the leaked, finalized ROM for the Sprint 7 Pro, which hints as near release.
To date, the official time frame for a CDMA Windows Phone 7 is sometime during the first half of 2011 (March would qualify). This time frame also mirrors the release date (early March) for the first WP7 update, "NoDo", that will contain CDMA support as well as copy/paste and performance enhancements.
There was speculation that the "NoDo" update was delayed due to carriers. Could the carrier delay have been to allow Sprint time to get ready for a Windows Phone launch? Nothing official from Sprint or Microsoft confirming this but March will be here before you know it.