Apply your sneak attack damage to all your attacks

3.5 Edition Rules:

We applied our sneak attack damage to a rogues first attack for a long time.   We finally discovered that we were playing it wrong, and immediately our rogues became must more dangerous in combat.   The correct method is to apply sneak attack damage to all rogue attacks that qualify for a sneak attack.   This means that an 8th level rogue, with a Base Attack Bonus of +6/+1 and wielding two weapons and thus getting 3 attacks (2 from his primary hand and 1 from his off hand) gets to apply sneak attack damage to all 3 attacks.   If he hits with a long sword in his primary hand twice and a short sword in his off-hand once, the damage would be (d8+ 4d6) + (d8+4d6) + (d6+4d6). That is potentially a lot of damage.
Source: http://www.wizards.com/default.asp?x=dnd/rg/20040217a