It came as a bit of a surprise, but both Apple and AT&T sold out of their iPhone 4 preorder stock yesterday. Despite the hardships of getting through on either company's systems, there were a large number of people who got their preorder on — 600,000 people to be exact.Apple released a statement this morning apologizing for the malfunctions and messy preorder situations, saying, "It was the largest number of pre-orders Apple has ever taken in a single day," and the sales numbers were "far higher" than expected. Additionally, AT&T released a similar statement to its employees saying that its first-day sales were "10 times higher" than that of the 3GS. One other twist to the AT&T story — all preorders of the iPhone 4 have been suspended on websites and stores, presumably to process all those handwritten preorder slips. You can still reserve a black iPhone 4 on Apple's website, but you'll be getting it just in time for your Independence Day festivities on July 2. Otherwise, plan on being in line at your nearest Apple store when it opens on June 24 at 7 a.m.