Apple Inc. said Monday it sold more than 300,000 iPads in the U.S., including preorders, on the first day the device was available. The company didn't give a precise figure, but the tally was below the estimates of some analysts. Buyers flocked to stores starting Saturday after weeks of publicity about the tablet-style computer. Apple hadn't offered iPad sales forecasts, but over the weekend, Piper Jaffray analyst Gene Munster more than doubled his initial first-day sales estimate to between 600,000 and 700,000 units, including preorders, based on longer-than-expected lines at stores and high expectations for online preorders. He had also...