The official Pokémon website has announced that the Macintosh client for the Pokémon TCG Online game has finally been released. The system requirements are extremely high and they recommend people use an i7 Mac! Below are the details.

Mac Gamers - Start Playing Pokémon TCG Online Today!

A whole new audience can join in on the fun with a Mac-compatible game client!

Mac users have waited patiently for an opportunity to join PC users in battle, and now their perseverance has paid off. Both the Mac and PC versions of the Pokémon Trading Card Game Online game client use the same servers, so Mac users will be able to battle, trade with, and befriend PC users seamlessly. Get the Mac client now on the Pokemon.com/TCG download page! Check the system requirements below to make sure you’re ready to play.

This new update also adds the new Pokémon TCG: Black & White—Boundaries Crossed expansion to the game. This expansion brings a mix of new Pokémon-EX, such as the Boundary Pokémon as both Black Kyurem-EX and White Kyurem-EX. Players can also take advantage of the new ACE SPEC cards that are so powerful, players can only include one in a deck!

Remember that the Pokémon TCG Online game is still in beta, and players may encounter bugs during gameplay. In the event that this occurs, make sure you submit a ticket via the Pokémon Support Portal or visit the Open Beta & Support section of the forums. Feedback from the community plays a critical role in improving the Pokémon TCG Online, so be sure to have your voice heard!

The system requirements for the Mac client are:

Recommended:
Mac OS X 10.6
CPU: 2.3 GHz Quad-Core i7
RAM: 4GB 1600MHz DDR3
VIDEO: Intel HD Graphics 4000
VRAM: 256MB

Minimum:
Mac OS X 10.6
CPU: 1.5GHz Dual Core Processor
RAM: 2GB
VIDEO: Intel HD Graphics 4000
VRAM: 256MB

Source: http://www.pokemon.com/us/pokemon-news/tcg_tcgo_mac-2012-11-26/