http://sprint.m.delivery.net/w/webVi...H&sc=&k=1ab7Y7
If you look at the bottom of the ad under the "Get unlimited web..." it says it's required. Engadget, who is supposedly at the NYC launch event also confirmed that it's a
mandatory addon if you want the EVO.
Really a kick in the nuts to anyone who isn't in 4G coverage, which quite frankly is pretty much almost everywhere.