There will be a Pokemon TCG tournament at Kumoricon this year. We will be using the current floor and game rules, which can be found
here, along with a bunch of other useful information on the game.
The event will a Modified Constructed tournament, although it might not be sanctioned. There will be prizes. Entry is free. I don't play the game myself, so I can't really go into more detail.
Here is a list of sets that I understand to be currently legal:
Diamond & Pearl
Diamond & Pearl – Mysterious Treasures
Diamond & Pearl – Secret Wonders
Diamond & Pearl – Great Encounters
Diamond & Pearl – Majestic Dawn
Diamond & Pearl – Legends Awakened
Diamond & Pearl Trainer Kit
POP Series 6 Promo Cards
POP Series 7 Promo Cards
POP Series 8 Promo Cards
All Black Star Promos numbered DP01 & higher
With the exception of basic Energy cards and previously printed cards that appear in Modified legal
sets, players may not use cards from Pokémon sets prior to Diamond & Pearl. Players
using previously printed cards that appear in Modified-legal sets must play those cards using
the wording of the most recent printing of the card. New sets are allowed as soon as the
product has been released in that rating zone.