The 2013 Global Showdown has been announced. Registration runs from July 18th through July 25th or until the participant limit of 50,000 is reached. The Showdown itself will start at Midnight on the 26th of July and will run through the 29th. It will be in a single-battle format, you’ll be able to bring between 3-6 Pokemon to choose from. It is a national Pokemon format, so you can use whatever Pokemon you want with the exception of Chatot, as well as the moves Sky Drop or Dark Void.
For a full set of rules for the last worldwide wi-fi competition for Generation V can be found by clicking here.