|From the D&DO site:|
As the preorder access period draws to a close we'd like to remind preorder players that you must enter a retail key in order to continue playing DDO after March 5th. For those preorder players who have retail keys but have not redeemed them yet, we recommend you enter your key at https://billing.turbine.com on Saturday, March 4th in order to avoid any "landrush" issues that may occur with the billing system on the 5th and 6th.
Although most retailers currently do have DDO on their shelves, if you are unable to obtain a retail box, keep in mind your account and character information will be saved and become available to you once you redeem your retail key. So there is no need to worry about losing anything if the retailers in your area don't have boxes yet.
We look forward to continuing to see all of you in Stormreach™!