I noted this piece a while back; there's a Part II. And a link to this story:
One night last February a Taliban suicide bomber tried to infiltrate the army barracks where 50 soldiers were sleeping. But the bomber was taken completely by surprise when the three dogs attacked him, holding him back by biting his legs, finally forcing him to detonate the 24lbs of C4 explosives he had strapped to his body. The attacker never made it to the threshold.
However, the blast did damage enough. As one soldier recounts the explosion was big enough that the shrapnel alone caved in a wall. Five soldiers were injured and two of the dogs were seriously wounded. Sasha, the third dog, sustained wounds that were too severe and she had to be put down. The soldiers nursed Rufus and Target back to health.
A semi-personal note: during his first Iraq tour, son mentioned a couple of the dogs that'd been adopted, and one of the things he said was that they very quickly learned "If they're wearing ACUs, they're one of us; if they're not..." A local working on the base saw one of the dogs watching him and threw a rock at it; by the time they dragged the dog off him, it was time for a serious trip to the hospital. So think of what three pissed-off dogs protecting their turf and pack were doing to that bastard.