It has been somewhat quiet on the Pokemon front, with Pokemon Black and White being limited to WiFi downloads since the launch back in March and only the 2011 Pokemon World Championship Series in the news since.
However, Nintendo has a Pokemon movie going to DVD, and that is just the thing to get them to cough up a download event with a special Pokemon.
The movie in question is Zoroark: Master of Illusions, and so naturally Zoroark is the Pokemon available at the download event.
From September 18th through September 25th you will be able to download a special level 50 version of Zoroark at Toys R Us. Find the details here.

Previously, the only way to get Zoroark was to have downloaded and transferred the three shiny legendary Pokemon from the Pokemon Black and White pre-release events. If you missed that, you now have another opportunity to get Zoroark.
In addition, Pokemon.com is running a number of additional promotions to go along with the release of the movie to DVD, including a Win With Zoroark Sweepstakes that runs through the end of September. The prizes include copies of the movie, but the grand prize is a Nintendo 3DS and a full suite of Pokemon Black and White games and accessories.

The download event is for Pokemon Black and White only. All of the details are available at Pokemon.com.