We're knee deep into Sprint's "Strategy/Network" update. The big (yet unsurprising) news is that, yes, it's moving to LTE. It'll be run on Sprint's 1900 MHz spectrum, with other spectrum to follow, including LightSquared's 1600MHz spectrum.
The first markets and devices are expected to be available in mid-2012.
Wimax devices, like the HTC EVO 4G, EVO 3D, Samsung Galaxy S II Epic 4G Touch, and others, will continue to be sold through 2012.
Sprint's Direct Connect service, which is replacing iDEN, launched last week. It's got broader coverage, and migrations are expected to be complete by mid-2013.