As part of the build-up to the mid-March release of Pokemon HeartGold and SoulSilver, Pokemon.com has announce that there will be another download event at GameStop.
While the dates for this download event have not been announced, I would have to think that February 28th through March 14th might be a reasonable guess. That would mirror the dates for the recent Pichu event and would tie right in to the March 14th launch date for Pokemon HeartGold and SoulSilver.
More details, such that they are, at Pokemon.com.
[Edit: The download dates have been announced.]
The Ancient Gaming Noob 