http://www.engadget.com/2011/10/21/sprint-to-nix-unlimited-from-mobile-broadband-and-hotspot-plan/

Well so much for their millions of dollars they spent marketing "truly unlimited". I guess this is the last USA carrier you could get unlimited data - so now we have no choice but to be screwed. On top of that they're not grandfathering in anyone that has unlimited plans now so they could keep those plans either - so come next month no more unlimited cell data - from anyone in the USA.
Perhaps if they're network can't handle the bandwidth traffic they should a) quit signing up more people on it or b) upgrade their network to handle all the devices they've already sold.