couric: tonight, tiger talks. what i did is not acceptable. and i am the only person to blame. couric: and gives a dramatic and emotional apology. i m katie couric. also tonight, the battle for marjah and a cbs news exclusive. we take you inside an enemy bunker used by taliban snipers to fire on u.s. troops. the school-issued laptops had cameras. did teachers use them to spy on students? and in vancouver, the american takes home the gold, but the russian claims he did one turn better. captioning sponsored by cbs from cbs news world headquarters in new york, this is the cbs evening news with katie couric. couric: good evening, everyone. it was quite a scene today. one of the most famous people in the world, known for being cool under pressure, standing humbly and nervously before a national audience on live television. and apologizing. tiger woods spoke publicly for the first time about the scandal that destroyed his image, jeopardized his marriage, cost him lucrativ