#1 - No need to buy Firecore's Atvflash software. I did and haven't been able to use it because it sucks.
#2 - Update iTunes, and do a restore on your Atv. This will ensure that the Atv is up to date and at factory default settings.
#3 - Go to greenpoison.com and download the free software for your operating system.
#4 - Follow the on-screen instuctions within the greenpoison .exe ( this may take a couple trys, but it will work)
#5 - After jailbreak is complete, wait 2 minutes before disconnecting your Atv from your computer.
#6 - Now plug Atv into your t.v. and you'll see the greenpoison button. Click and install.
#7 - Follow instructions to restart Atv and now you'll see a Nito t.v. button. Click and install.
#8 - Now you can install XBMC, and use it to stream your audio, video and pics from your network without needing to use
any iTunes accounts or Apple formats. XBMC comes complete with the codecs needed to play all
your favorite files.