Radio Free Europe has details:
Lars Vilks, a Swedish cartoonist whose sketch of the Prophet Muhammad enraged many Muslims, was head-butted today while giving a lecture about freedom of speech. Vilks, who depicted the Prophet Muhammad with the body of a dog in 2007, said he was assaulted by a man sitting on the front row as he spoke at the University of Uppsala, about 70 kilometers from Stockholm. A spokesman for the Uppsala police said about 20 people tried to attack Vilks after interrupting his lecture, adding that the police had to intervene to stop them.
Hamilton Nolan fumes:
The fact that so many American media and academic institutions have caved into the imagined fear of such religious fascists is shameful. If the free societies of the world can't stand up for a person's right to draw a fucking cartoon without becoming the victim of a multinational assassination plot, well, we lose. And if people's faith in their god is not strong enough to allow them to laugh off and dismiss an offensive little drawing, they lose.