I talked to UPS this morning since on their tracking page it did not mention a delivery date (yes, I know it's supposed to be April 3). The UPS agent indeed confirmed Saturday delivery and he added that Apple had made special arrangements with UPS to deliver pre-ordered iPads on April 3. So far, this whole enchilada seems well organized.
By the way, want to have some fun? Visit eBay and key in iPad. You'll find over 5,000 listings includind 200-plus for iPads that no one has yet.