Weapon Finesse

Weapon Finesse

Type: General
Source: Player's Handbook v.3.5

You are especially skilled at using Light weapons, one that can benefit as much from Dexterity as from Strength.

Prerequisite: Proficient with weapon, base attack bonus +1 or higher
Benefit: With a light weapon, rapier, whip, or spiked chain made for a creature of your size category, you may use your Dexterity modifier instead of your Strength modifier on attack rolls. If you carry a shield, its armor check penalty applies to your attack rolls.
Special: A fighter may select Weapon Finesse as one of his fighter bonus feats.

Natural weapons are always considered light weapons.

For Spell Casters: You can designate touch spells as light weapons so as to add your Dexterity modifier on your melee attack rolls with such spells.