To me it looks like Sutil missed his braking point thus he was a bit too long for the corner. Raikkonen realized it too late and tried to compensate by braking harder but he lost it because of the bumps on the track at this place.
Attached screenshot is showing Sutil countersteering into the corner
before being touched by Raikkonen.
Video of the accident:
http://www.megaupload.com/?d=E98DEXVK
MPEG2 PS Interlaced
Look closely at the video and you'll see Sutil's mistake.
Notice that I'm not saying it was Sutil's fault. But Sutil did a mistake which is, in my opinion, the cause of Raikkonen's mistake. This is very common in racing, you can even test that in LFS, if you take a corner a bit wide there are 80% of chances that the car just behind you is going to do the same thing. Most of the time people look at the car in front of them instead of looking at the track which is the only reference.