How to stream from ATV.

I own and Ipad and recently I've downloaded an app called Air Video, from it I could stream videos from my Mac to my Ipad, but my library is currently on my ATV so it would be nice to be able to stream to it across my wifi network and perhaps online, I've seen someome who acomplished something similar to this using XBMC but I do not know how to operate XBMC properly, I attempted to copy my from my MAC to my ATV but does not enable.

Can this be done? if so how.