Prone Attack( Complete Warrior, p. 103)
[Fighter Bonus Feat, General]
You can attack from a prone position without penalty.
Lightning Reflexes (PH) , DEX 15, base attack bonus +2,
You can make an attack from the prone position and take no penalty on your attack roll. If your attack roll is successful, you may regain your feet immediately as a free action. Opponents gain no bonus on melee attacks against you while you are prone.
A fighter may select Prone Attack as one of his fighter bonus feats