[Anarky]

No, throwing the shoe isn't. As the internet woud say, "lrn2culture." The problem herein lies with the sole of the shoe, which is in the middle east a sign of utter disrespect (not insult). And it's easily explained. You see, you stand on the soles of you shoes all day long, which basically means that everything that is under your shoes is beneath you..

In the middle east as well as in parts of asia, it is considered very disrespectful to show a person the soles of you shoes since it is interpreted as "You are beneath me." And throwing the soles of your shoes at someone (normally with shoes attached) is just a one-up for that.

EDIT: As to this insult in real life, it starts with you sitting there with crossed legs ( having the ankle on your thigh) and you show the sole of your shoe to your neighbour who happens to be of arabic origin, he'll be insulted. Not to the point where he'll be damning my ancestors (a real life insult in arabic) but to the point where you'd get the odd look or so. Most people, however, do acknowledge the fact that we have different moral values and that the showing of the sole isn't an insult in our culture, so they will tell you that you should probably watch that a bit in the presence of arabs.

As for insults per se, the arabic language holds a lot of very beautiful insults among which are "Curse your mother's faith," "Damn your seventh grandfather," "A shoe is on your head!" and - here's a really awesome one - "I hope that 60000 dicks will dance on your mother's pussy." You see, arabic is a language that is really heavy on imagery.

As for what Bush should do now... Do not go "Shoe... meh" as he wouldn't just disrespect the shoethrower but also every arab speaker there is and follower of the culture. Maybe a "I'm sorry the guy feels so strongly about me, but America will stay her course and freedom will prevail."