After 6 rounds, it's Magnus Carlsen 3.5, Viswanathan Anand 2.5.
Superb chess, even though it's nearly all over my head. You can read lots of analysis on the web, including here.
Until I read the analysis, I didn't understand exactly where Anand lost, but I'm comforted that after I read the analysis, I understood it.
Me, I just love the fact that they both play 1. e4.