Apple officially opened preorders for the iPad today, and despite mass criticism and mockery online, tens of thousands have already purchased the slate. In the first two hours alone, around 51,000 orders were placed for the tablet, according to analyst Victor Castroll. That figure isn't official, of course, and it only includes Apple's online store. It also represents orders, not units, and some folks surely purchased multiple iPads at once.

The iPad starts at $499 for the 16GB model with Wi-Fi, and the 32GB and 64GB versions run $599 and $699. All of them can be purchased through Apple's online store, and will be delivered for free on April 3 or April 5 if Saturday shipping isn't available in your area. In-store pickup is also available for April 3. The 3G-equipped iPads carry a $130 premium, with 16GB, 32GB and 64GB options priced at $629, $729, and $829. Those models will ship in late April.