That would be useful to know. If you're just wanting to play content without modifying the files, then there are plenty of DLNA options for iDevices that can then be AirPlayed to the ATV. Air Video HD is a good example - the server side is free, the app is relatively cheap, it lets you access your content remotely & without file type restraints, and it supports AirPlay.Can't do it. That's the reason the ATV2 goes for so much money on eBay/craigslist/etc.
What are you trying to accomplish with the JB? Maybe we can help you with that.