So it turns out that the Amazon page for Seven Deadliest Unified Communications Attacks has the wrong info on it. I confirmed this morning with my editor at Syngress that the launch date is not April 15, as listed on Amazon, but instead April 28th. So... a little bit longer to wait... :-(
(Speaking of the wait, have you pre-ordered the book yet? If you do, you'll get a copy as soon as they start shipping...)