http://www.pokemon.com/us/pokemon-news/vg_blackwhite2_meloetta_distribution-2013-02-04/ ^ | NEW MELOETTA EVENT at GameStop. Yes, I looked first to see if this had already been discussed. From what I searched in this article and from my friend (it was my friend who told me about this at school) it's available for B/W 1 and 2. It runs from March 4th to...well...an unreleased end date. It does state it's limited time only.
It's there now. Just finished reading it.
http://pokemondb.net/pokebase/meta/9241/event-information Shiny Xerneas answered with it.
Jovial Jolteon also answered with it