2011-09-22 : If, during the enchanted player’s declare attackers step, a creature they control is tapped, is affected by a spell or ability that says it can’t attack, or hasn’t been under that player’s control continuously since the turn began (and doesn’t have haste), then it doesn’t attack. If there’s a cost associated with having the creature attack, the player isn’t forced to pay that cost, so it doesn’t have to attack in that case either.

2011-09-22 : The enchanted player still chooses which player or planeswalker each creature they control attacks.