Here is what I found from the TCGO website.
NEWS
Head-to-Head Play Now Available in Pokémon TCG Online
Posted: August 20, 2012 by JAQQ
The release of the TCGO game heralds a significant step forward for the Pokémon TCG Online. This version of the game client reintroduces the core components of multiplayer, as well as providing players with access to the Black & White–Dark Explorers and Black & White–Dragons Exalted expansions.
What features have been added?
The TCGO game adds the Versus Mode, Deck Manager, Collection, Avatar Builder, and Friend List components to the game, along with more than 230 cards now also available in two new expansions!
Versus Mode - This game mode contains Practice Battle, Player vs. Player, and Friend Battle.
Practice Battle gives players the opportunity to battle against computer-controlled opponents of varying difficulty levels. Unlike the Trainer Challenge, players can use custom-built decks for these matches!
Player vs. Player randomly pairs the player up against a human opponent from anywhere in the world! Unranked matches are available now, and ranked matches will be available in later game updates.
Friend Battle allows players to challenge people on their Friend List to a match. All Friend Battle matches are unranked, making it a great way for friends to playtest decks before unleashing them on the public!
Deck Manager - This game mode makes it easy to review your unlocked theme decks and build custom decks from the cards in your collection. You can select a deck box and coin to use with each deck.
Collection - This game mode shows a player all of the cards, packs, and avatar items that they unlock. Additionally, players can view the cards, packs, and avatar items they mark for trade or review.
Avatar Builder - This game mode helps you build a custom avatar, changing their face in the game. The overhauled interface makes it easier to find your favorite items and build the coolest avatar possible!
Friend List - This game mode allows you to tag other players as friends, making it easier to challenge them to battles or create trades.
New Expansions - Two additional card expansions are now available, Black & White-Dark Explorers and Black & White-Dragons Exalted. These new cards expand your deck-building possibilities.
What features will be available in the short term?
In addition to further polishing the existing game components, future releases should add Trading, Tournaments, Gems, Avatar Builder, and Play Style to the game client. Additionally, the TCGO team is planning to release a Mac-compatible game client before the end of 2012.
What features will be available in the long term?
We have some very exciting plans for the Pokémon TCG Online. We are committed to providing a world-class game experience for our fans and will continue adding new functionality for both the single-player Trainer Challenge and multiplayer to broaden and deepen the player experience.
How do I download the new version?
If you have already downloaded and installed the Pokémon TCG Online game already, the game will automatically update to include the features mentioned above the next time you login. If you have not yet downloaded the game, click here. Click the Download button and follow the instructions (more information can be found on the FAQ here).