The official TCG website has posted information about two of the upcoming cards that will be part of the new expansion 'Platinum'. Below is information about the two cards. You can click on either card to get a higher resolution.

Honchkrow [G]
Pokémon TCG: Platinum introduces new Pokémon owned by members of the sinister Team Galactic. While Honchkrow is normally a Stage 1 Pokémon, Honchkrow [G] (Platinum, 77/127), owned by Cyrus, enters the game as a Basic Pokémon. For no Energy, the Honcho's Command attack allows you to search your deck for up to 2 Stadium cards or Trainer cards that has Team Galactic's Invention in its name. This is a great way to fill out your hand with some cool new cards - stay tuned to Go-Pokemon.com for more information on what Team Galactic's Invention cards can do. Honchkrow [G]'s Target Attack allows you to put 2 damage counters on 1 of your opponent’s Pokémon. If that Pokémon already has any damage counters on it, the attack does 20 damage plus 20 more damage. Honchkrow [G] proves that Team Galactic enters the battle with some tough new Pokémon in its collection!

Giratina
Appearing in the Pokémon TCG for the first time in its Origin Forme, Giratina (Platinum, 10/127) is a hefty Basic Pokémon with 100 Hit Points and 3 attacks. For 2 Colorless Energy, Giratina's Over Slash attack does 10 damage to each of your opponent's Pokémon. This is a great way to spread around damage, allowing you to pick off a Pokémon seeking refuge on the Bench. Dark Wing Flaps does 20 damage, and then allows you to choose a card from your opponent's hand without looking. Once you've checked to see what card it is, your opponent must then shuffle that card into his or her deck. The damage from Dark Wing Flaps isn't massive, but if you pick the right card, you can disrupt your opponent's game plan. If you need to pack a bigger punch, Giratina's Wrack Down attack does 60 damage - no strings attached!

Source: http://go-pokemon.com/tcg/cards/featured/pl1/