Which meant neither Sprint's or Verizon's network were 4G, but that didn't stop them from advertising.
In December, the ITU changed their mind and now WiMax, LTE, and HSPA+ can be called 4G: http://www.intomobile.com/2010/12/18/itu-reverses-its-decisi...
At this point, I think 4G is just mostly a marketing phrase now.