Dude thats old news. it has been known for quite somtime that sprink has been equiping their towers with WiMAX they hop to finish by 2012. this was reported on BGR and reuters 6 months ago.
and yeah Sprint has been making announcements about this for awhile but I doubt RIM has any intentions for atleast 5-7 years. Their goals of being the most secure phone makes them a little slow to adopt new technology in my opinion.
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