Hmmm... Crytek uses the same site for Warhead as they used for teasing Crysis. Let the speculations begin
http://www.crysis-thegame.com
http://www.crysisthegame.com
Source: http://www.incrysis.com/index.php?option=com_content&task=view&id=659
http://www.crysis-thegame.com
http://www.crysisthegame.com
Source: http://www.incrysis.com/index.php?option=com_content&task=view&id=659