Just back from Berlin a few hours ago.. and I visited Kreuzberg, nice area!
I went with some friends to Room77, small pub in the area very well known. They do accept bitcoins and I must say the process was very fast, no more than 5 seconds and I paid for our beers. The pub has a huge illuminated Bitcoin symbol and many signs inside.
I must also say that it's not exactly like described in newspapers.. I just found two shops accepting bitcoins, Room77 and a records' shop, nothing more. But the experience was nice and the beer tasty!
I haven't gone yet! I'm leaving I believe on the 29th of August (I'd have to check though).