You can fight with a weapon in each hand. You can make one extra attack each round with the second weapon.
Prerequisites
Dexterity 15.
Benefit
Your penalties on attack rolls for fighting with two weapons are reduced by 2. In addition, you may make an off-hand attack with any standard action attack or full attack, including when charging, but not when using a special attack or maneuver (such as a trip or grapple attempt).
In addition, when wielding two weapons (not including natural weapons or unarmed strikes) or a double weapon, you gain a +1 shield bonus to your AC. When you are fighting defensively or using the total defense action, this shield bonus increases to +2.
Special
A character with the Improved Unarmed Strike or Brawl feat who takes this feat gains an off-hand attack with his unarmed strike, using only one-half his Strength bonus as normal for off-hand attacks. A monk, however, retains her full Strength bonus to unarmed strikes, even when attacking with her off-hand.
A creature with more than two arms that possesses this feat may still make only the one extra attack as a standard action or as part of a charge, though it gains all other benefits of this feat. It requires a full attack action to attack with all weapons it wields.
Normal
Without this feat, the attack penalty for fighting with two weapons is -6 (or -4 when using a light weapon in your off hand). You must also use a full attack to attack with more than one weapon in a round.