Asperger's is very poorly understood, and this misunderstanding is really hard on suffferers (I am one.) The cause of all the varied symptoms is that we have a slight delay in processing sounds, as explained in this article: http://www.newscientist.com/article/dn16174-brains-of-autist...
This means that if you say "Hi" to me, I know instantly that you said a word one syllable long, but it takes me a fraction of a second longer than a normal person to decipher the word as "hi." This isn't a problem when a person says just one syllable. But in a whole sentence, the delays snowball until I miss a big chunk of the sentence, especially if the person speaks quickly. That's why, in danteembermage's example, his son "has a hard time finding objects using verbal instructions 'grab your shoes buddy.'" If you handed him a piece of paper that said "grab your shoes, buddy," he would get the shoes as fast as anyone.
Poor speech comprehension is the root of all unusual Aspie behaviors. ShabbyDoo's son "physically cringes when there's lots of noise/confusion." The confusion comes because there is too much noise and not enough signal. Aspies shy from social situations because they can't understand what people are saying.
Even things that seem like deep-down problems can easily be explained by poor speech comprehension. The article spends a lot of time on empathy, but empathy is not an emotion, it's a social skill. You act like you care about somebody else's problems so you get along with them better. Aspies suck at it because they have a hard time understanding what people are saying, and they just have less chance to develop social skills in general, because it is so hard for them to talk to people.