On this Google Map you can see all beer tents of Oktoberfest. When the pin of the tent is green the tent is open in the moment. When the pin is red, the tent is cloesed because of overfilling. One click on the respective tent and you get further information about the tent.
Also marked in this map are the positions of the live webcams. Just click on the respective webcam on the map and you'll see the actual live pic from the Oktoberfest.