There is a blog where information about the new Pokémon Sun and Pokémon Moon games will be gathered. Apart from information about new Pokémon, the story, charachters, region and etc. this blog will collect information on the possibility of Rom's for Pokémon Sun and Moon and on what platforms this will be possible.
As soon as technical possible of course, the new blog will also host the files for the
Pokemon Sun rom and Pokemon Moon Rom.
So for all the latest information on Pokémon Sun Rom and Pokémon Moon Rom, please visit
http://pokemon-sun-moon-rom.blogspot.com