The Intertubes are exploding this morning with reports of people getting iPad shipping confirmations via email. The only problem is that they're shipping from Shenzhen, China (using UPS Expedited service) and unlikely to arrive any earlier than the contracted, April 3 date.
MacRumors notes that Apple has coordinated with UPS in the past to hold early deliveries until launch day making it unlikely that UPS will deliver any units in advance of the Saturday, April 3 embargo date. Unless you know your UPS drive really well.
You can check to see if your iPad is "on the truck" by plugging your order number into Apple's order status page. Unfortunately, mine is still listed as "Not yet shipped."
What about you?