Link to details at Huffington Post, and CNN has posted this video. Shortly after the incident, Cooper tweeted, "Its getting really bad in front of Egyptian museum"—all of the Twitter feeds I'm following from folks on the ground there point in the same direction. The protests are now being flooded by pro-Mubarak thugs, and various state employees paid to be present, and there are very high counts of injuries today. The situation sounds increasingly dangerous.
As an aside, I have plenty of complaints about CNN, but I have nothing but respect for Anderson Cooper's work. Dude is for real. From the tweets, sounds like he and his crew have been awake for four days solid since landing in Egypt. I think they're doing solid reporting under extremely difficult conditions.
Katie Couric, Christiane Amanpour, and a number of reporters with Al Arabiya and Al Jazeera have also been beaten up by thugs who back (or are employed by) Mubarak.