Players of Pokemon Sun/Moon will at long last be able to bring over their precious Pokemon, caught in Pokemon X/Y and OmegaRuby/AlphaSapphire (or even earlier, and imported to those games), or in the Virtual Console re-releases of Pokemon Red/Blue/Yellow, to the newest games- Pokemon Bank has finally been updated to allow players to transfer their Pokemon over into the new games.
To induce users to use Bank, Nintendo and The Pokemon Company have announced that anyone using Bank will get a free Mewnium Z-Crystal, which allows Mew to use its Z-Move in battle – Genesis Supernova. Pokemon Sun/Moon are available exclusively on the Nintendo 3DS.
Source: Rheena.com