Good news abounds!
Amazon now says The Guide "Usually ships within 3 to 6 weeks," which is code for "Hey, it finally occured to us to order some copies of this book that we've been accepting preorders on for over half a year." My insiders say that they should actually be shipping all preorders in about two weeks.
Amazon customers, please post a comment when and if you get a message from Amazon indicating that the March ship dates were a big, hateful lie, designed to cause strife and keep you from making a movie.
Some enterprising Amazon Marketplace sellers have some copies for sale, some of which are available now. Check out "More Buying Choices" on the Amazon product page.
Barnes & Noble show that they ship The Guide within 24 hours. Rock on, BN.
And of course Peachpit is still happy to sell it to you online or at Macworld next week.