The Qu'Ran does speak about respecting "people of the Book" (Jews and Christians). But it also talks about killing infidels (all non-muslims) or forcefully converting them (see Tai Fu's comments later in this thread). Muslims are selective readers: peaceful Muslims choose the first verses and violent Muslim radicals choose the second. The current news stories (and 9/11, Cole, suicide bombers, anti-Jewish violence) about Muslm fanatics burning flags and embassies and calling for killing blasphemers (and they get to define blasphemy) clearly shows which group is most prominent.
I have no problem with Muslims being upset either, but violence destroys freedom. To imply as you do that violence is a legitimate expression of the wrath of these people is just plain wrong. These Muslims are not just upset; they are trying to force everyone else to agree with their religious understandings, and that I will not do. Muhammad was a human being and ridiculing a human being is not, by definition, blasphemy. To make his turban into the shape of a lit bomb as the cartoonist did was right because it showed how violence is being used and promoted by some Muslims. And the irony of these protestors is that they chose to protest using exactly the same violent methods the cartoon they are objecting to demonstrates. So was the cartoon true? Absolutely.
You also say "It only becomes politically correct to ridicule a group if that group allows it." That is false. Political correctness does not result from the reaction of a ridiculed group. Remember the "artist" whose "art" product was a crucifx of Jesus upside down in a jar of urine? That was blasphemy because Christians do consider Jesus to be divine. Sure Christians protested, but they didn't burn down art galleries and issue religious edicts calling for the killing of the "artist." On your view Christians seem to deserve to be be marginalized because they did not use violence to attempt to prevent it.
Then you write "Respecting another's beliefs doesn't mean you agree with them." This shows a fundamental misunderstanding because from the point of view of radical Muslims to respect Islam is to agree with it. That's the end purpose of these violent protests; to violently force us all to agree that saying anything negative (whether it's true or not) about Islam, Muhammad, or the Qu'ran is blasphemy punishible by death. Never underestimate the ends they are willing to go to in order to re-make the world with Islam in total control. It's not Bush, the Patriot Act, domestic surveilance, etc. that should be our first concern. Those are issues worth discussing later, but our first concern ought to be that we prevent the Islamic radicals from re-making the world as they want it. And because they use violence to promote their view, the only way to resist them is to use violence in return. That's called self-defense, and I believe our freedoms, limited or not, are worth defending. Larry Lobdell Jr.