Update: Some early pre-order folks are saying their devices are supposed to arrive on the 25th. It might only be newer pre-orders that are going out on the 30th.
If you're planning to pick up Samsung's latest and greatest on AT&T's LTE network the instant it's available, start checking your email for tracking numbers on April 30th. That's when pre-orders for the Galaxy S 4 will begin going out to customers. However, if you didn't pre-order the device, you might actually be able to get it a few days early on April 27th. Take that, early birds!
AT&T's online purchase page for both the white and black 16GB Galaxy S 4 now states the device will ship on April 30th in no uncertain terms.