The Pokémon Video Game Championships are returning for 2010 and tournaments will be starting in the spring in cities across the world. More information about the tournaments will be announced around March 14th when Pokémon HeartGold and SoulSilver Versions arrive in stores in the United States and Canada. Below are the rules for the tournaments that were announced on the official website.

Returning participants will notice that most of the rules and guidelines are the same as last year, but we've been working hard to make exciting changes that will make the 2010 Pokémon Video Game Championships better than ever! These changes include:

• Players now using Pokémon HeartGold or SoulSilver Version games exclusively
• Pokémon Level 51 and higher being automatically graded down to Level 50 for the duration of the battle using a new auto-leveling feature
• Each Pokémon keeps all of the moves it knew before being adjusted
• Pokémon that evolve after Level 50 don't devolve
• Any Pokémon below Level 50 will stay at its current level
• Virtually every Pokémon found in the National Pokédex of Pokémon HeartGold and SoulSilver Versions is eligible, including Pokémon traded in from earlier games, with the following exceptions:
• Arceus, Celebi, Darkrai, Deoxys, Jirachi, Manaphy, Mew, Phione, and Shaymin cannot participate
• A team cannot contain more than two of Dialga, Giratina, Groudon, Ho-Oh, Kyogre, Lugia, Mewtwo, Palkia, and Rayquaza during a battle

Source: http://www.pokemon.com/us/news/op_vgc_2010_announce-2010-02-08/