At the beginning of enchanted player's first upkeep each turn, that player gets an additional upkeep step after this step.
9/25/2006 Paradox Haze targets a player when it's cast, and it enters the battlefield attached to that player.
9/25/2006 If two Paradox Hazes enchant the same player, they'll both trigger when that player's first upkeep of the turn begins. The player will get two additional upkeep steps.
9/25/2006 Abilities that trigger "at the beginning of [your] upkeep" will trigger at the beginning of each additional upkeep as well.
9/25/2006 If echo triggers during the first upkeep, it won't trigger again during the second upkeep since the creature won't have enter the battlefield since that player's last upkeep.
9/25/2006 If an effect causes the enchanted player to skip his or her upkeep step, this ability won't trigger.