Along with rolling out of the iPads in some other countries, it seems like the devices might be available very soon for the U.S customers
http://www.notebookcheck.net/iPad-waiting-time-online-comes-down-to-less-than-a-week.74483.0.html
it's because all the stock went to retail. from day one, you could walk into any authorized reseller or appple store, and buy one without waiting. It was never sold out in stores.