First, Fortune follows the Apple Sanity Board (oxymoron?)who have been tallying order numbers from iPads purchased today. They’ve figured that between the start of sales at 8:30am ET until 10:30am ET, 51,000 orders were taken. While “50,000 iPads sold in two hours” makes a good headline, there were probably a few iPods and Macs sold during that time period as well. Apple receives 15,000 orders on a normal day. Silicon Alley Insider thinks 20,000/hour are selling, which from the above, seem pretty reasonable. MacDailyNews reports that people who change their order for in-store pickup won’t receive their iPads on April 3. Multiple iPad buyers have been told that in order to do such a change, the delivery order would have to be cancelled and a new in-store pickup order completed, but that iPad orders (which began this morning at 8:30am EST) have been “so overwhelming” that new iPad orders may not be available for in-store pickup on April 3. Earlier estimates were that Apple wanted to make 700,000 iPads in March and a million in April.