With iPad pre-orders opening today in the US, one analyst claims the that more than 90,000 iPads have been ordered in the first six hours of availability.

According to Fortune, analyst Victor Castroll has been tracking customer order numbers from the first day of iPad preorders and said that within the first two hours, there were approximately 51,000 iPad preorders.

The estimate, which takes into consideration that order numbers are issued for all online orders, not just iPad pre-orders, doesn’t include the 15,000 other online orders the US Apple store usually handles in a day.

Pre-orders were limited to two per person, and the estimate doesn’t take into consideration those people ordering more than one iPad, so it seems likely that the number is plausible.

Castroll commented to Mashable on the 90,000 estimate and said, “We’re at 90k in 6 hours. Keep in mind, this doesn’t include multiple orders but we have some dirty data from regular Apple business which now is about 4k orders out of the 88k orders. So, we estimate Apple has already sold about 90k today, not including in-store reserves.”

He continued to say that the numbers were an extremely good sign for a device that nobody was sure would actually sell.

“Looks like contrary to much speculaion about who would actually want one of these, like the iPhone, people are voting with their wallets,” Castroll said. “Considering these are just pre-orders for a product still three weeks out, iPad is home run.”