Improved Two-Weapon Fighting

Obsidian has mentioned the dual-wielding concept as well as it being a core DnD mechanic. This means improved two-weapon fighting is likely to be included in NWN2.

3.5 Improved two-weapon fighting
Type: General

Prerequisites: Dexterity 17, Two-weapon fighting, base attack bonus +6.

Benefit: In addition to the standard single extra attack you get with an off-hand weapon, you get a second attack with it, albeit at a –5 penalty.

Normal: Without this feat, you can only get a single extra attack with an off-hand weapon.

Special: A 6th-level ranger who has chosen the two-weapon combat style is treated as having improved two-weapon fighting, even if he does not have the prerequisites for it, but only when he is wearing light or no armor.

External resources

 * NWNWiki:Improved Two-Weapon Fighting