Because FIFA has instituted a rotation between the confederations in awarding the World Cup, the next time a North American country will be hosting the tournament should be in 2018 (Asia 2002, Europe 2006, Africa 2010, South America 2014).  As we hosted the 1994 World Cup, I would think Mexico and/or Canada would be the frontrunners to host that tournament.  I would guess that the next time the U.S. will host the tournament will be in the year 2038.