Check out Dr. Oz's website. There is a lot good, current information. And this is where the publicity and ruckus started (it was actually measured before, but results were not widely pulicized).
Here is the general gist:
Okay, so from what I have been reading, the arsenic comes into the picture because it has been used as a pesticide in foreign apple orchards (and can be found in water, etc). It was banned as a pesticide here a long time ago. But we recieve the concentrated juice from 7 different countries, including China. So if your juice comes from concentrate, that could be trouble (make sure the lable says "not from concentrate"...or if it says "from concentrate" always, always put it back). The brands in question are Minute Maid, Apple and Eve, Motts, Juicy Juice and Gerber (AREYOUKIDDINGME???).
So, if your apple cider comes from 100% locally grown apples, especially organic ones, it should be fine. But don't forget to check all of the labels of the pre packeged foods in your house because apple juice/concentrate is used as a sweetener quite a bit. Especially in prepackaged baby foods.