You can fight with a weapon in each hand. You can make one extra attack each round with the second weapon.
Your penalties on attack rolls for fighting with two weapons are reduced. The penalty for your primary hand lessens by 2 and the one for your off hand lessens by 6. See the Two-Weapon Fighting special attack.
If you wield a second weapon in your off hand, you can get one extra attack per round with that weapon. When fighting in this way you suffer a -6 penalty with your regular attack or attacks with your primary hand and a -10 penalty to the attack with your off hand. If your off-hand weapon is light the penalties are reduced by 2 each. (An unarmed strike is always considered light.)
A 2nd-level ranger who has chosen the two-weapon combat style is treated as having Two-Weapon Fighting, even if he does not have the prerequisite for it, but only when he is wearing light or no armor.
A fighter may select Two-Weapon Fighting as one of his fighter bonus feats.