You'll just need to pop your head in the store and boot up in the game. Then head to the receive gift menu and select "get with internet".
Head over to any Pokemon center and get your Mew (and don't forget to save your game!).
We even went as far as saying it was "the most important, expansive, exciting monster-battling title since the earlier days of the franchise"
Want more? Check out our 48 other Pokemon X / Pokemon Y news stories!