Apple has officially stated that pre-orders for the new iPad are sold out, which probably doesn't come as a surprise to anyone who's watched the "shipping by" date at the Apple Online Store slip by a week or several weeks over the last few days. According to a statement Apple gave several media outlets, including CNET:
Customer response to the new iPad has been off the charts and the quantity available for pre-order has been purchased. Customers can continue to order online and receive an estimated delivery date. Beginning Friday, March 16, the new iPad will be available for purchase at Apple's retail stores and select Apple Authorized Resellers on a first come, first-served basis.
So if you haven't pre-ordered yet but still want to grab a new iPad on launch day, you'll be lining up outside an Apple Retail Store or hoping your local big box has sufficient stock of the model you want.
No word yet on when sales will start on Friday, but they're usually either early in the morning or at 5pm local time following a brief store re-dress. Hopefully Apple will provide that information this week.
If you're still not sure which new iPad model to buy, here's some help: