It used to take weeks for falsehoods to spread throughout the land. Now, with a few keystrokes and a good e-mail client, they can be circulated in a matter of minutes. But where can you turn to assure Uncle Walt that gangs of teens are not roaming the streets looking to swipe his kidneys? Try Straight Dope ( www.straightdope.com ), a site dedicated to enlightening the misinformed. The online home of Cecil Adams's syndicated column, Straight Dope tackles everything from misheard song lyrics to misunderstood scientific principles. Can you see an on-camera hanging during The Wizard of Oz ? No. Did Neil Armstrong muff his "One small step for man" speech? Probably not. What's the sound of one hand clapping? Um . . . it's kind of complicated. "Fighting ignorance since 1973," proclaims Straight Dope. "It's taking longer than we thought." Who knows? Maybe the Internet will speed things up.