The Army PFC that leaked the materials to Wikileaks should be hanged for treason.
However I'm a little concerned about prosecuting Wikileaks for publishing them because we generally don't punish media outlets for publishing leaked secrets.
Just think what the precedent would mean ... any media outlet or figure the current (or a future) administration wanted to get rid of would simply have some juicy tidbit leaked to them and then after it was published they'd claim it was classified and BAM they take out a voice against them. THAT would be a serious threat to free speech.