I didn't feel like reading through the whole thread but I noticed that some people were confused about this event.
Raikou: January 3 - 9
Entei: January 17 - 23
Suicune: January 31 - February 6
Celebi: February 27 - March 7 (Rumored)
To obtain your Pokemon, you must go INSIDE the GAMESTOP and an employee will transfer your Legendary to your DPt or HGSS game via "Wireless" an option under "Mystery Gift."
The Mystery Gift option is initially on the main menu of your HGSS game. If you are using DPt, you must enter a password in game to receive this option. (
http://www.serebii.net/platinum/mysterygift.shtml)
This is open to North Americans, meaning Canada gets it too. I suggest someone ask a Gamestop employee about the Celebi, as I already got my Raikou and won't be going back till Entei :D