You shouldn't have to jailbreak the thing at all. It should be fully working out of the box. If it isn't, somebody disabled the product, and that's the manufacturer's fault.
I just got an apple tv 2 and am wading through all the info about firmware, jailbreaking, etc. Not sure what the optimal firmware is (this is a big deal on iphones) or how to best approach streaming avis to the appletv, but I do find it intereting I can JB the latest...so I care! haha