Someone has put a great of effort into a wiki
on the cartoon situation. It is as generally even-handed a post as can be expected when you discover that the people at the root of this problem on both sides are obnoxious jerks.
This isn't battle between free speech and religious freedom, this is a petty political battle between two groups of mudslingers that has gotten out of hand. The easiest way I can think of characterizing this for Americans is to imagine the Minute Men taking on James Dobson.
The newspaper commissioned these cartoons. The specification was for anti-Muslim cartoons to run in a newspaper that is part of the "Denmark for Danes" movement.
Fearing that the actual cartoons might not be enough, the Danish imams "sexed up the dossier" with some photoshopped graphics that were never published anywhere when they visited Muslim countries for support.
The BBC tried to have a discussion by inviting on a moderate Muslim member of Parliament and a hard-line imam. It went nowhere. At one point the hard-liner called the MP a Blair puppet, and the MP asked why the hard-liner hadn't moved to Afghanistan when it was ruled by the Taliban if he was such a fan of Islamic law.
The people doing the rioting haven't seen the cartoons. All they know is what they were told. If the people doing the telling were the Danish imams, they were lied to, but why should anyone be surprised, it's not as if governments in the West don't lie to people so they can kill Muslims and destroy their homes.