You may remember an earlier post about this, so here's an update. The dates for the US regional championships have been announced (full info on the comment jump), and the existence of japanese, UK, french and german championships also announced - although the dates for these are still missing.
For all those who register for entry, a level 50 shiny milotic is also up for grabs - even if you don't make it into the championships themselves.
The official site also has information on the rules for the tournament, and more information on what to bring, etc. So get ready for battle, and good luck!
(Edit: As pointed out in the comments, the european dates are available. More info on the jump.)