Subduing Strike( Book of Exalted Deeds, p. 46)
[Fighter Bonus Feat, General]
You are adept at striking to deal nonlethal damage even with normal weapons.
Holy Subdual (BoED) ,
You can use any melee weapon to deal nonlethal damage with no penalty on your attack roll. If you are a rogue, you can deal nonlethal damage with your sneak attack even if you are using a normal melee weapon. This feat does not allow you to deal nonlethal damage with ranged weapons.
A fighter may select Subduing Strike as one of his fighter bonus feats.
If you use a melee weapon designed to deal lethal damage to deal nonlethal damage instead, you take a -4 penalty on your attack roll. Rogues normally can only use saps or unarmed strikes to deal nonlethal damage with their sneak attacks.