My status was updated this morning:
SPHL720WTS SAMSUNG L720 WHITE 1 2013-04-18
Status: Thanks for pre-ordering the Samsung Galaxy S4 16GB. You are one step closer to getting your phone. Keep an eye out for a shipping email with your tracking information. We will do our best to get it to you on or before Saturday, April 27. For questions, visit sprint.com/preorder. Since we will be processing many pre-orders so quickly, your tracking number takes a little longer to get to you than normal. Do not worry. Your tracking email may come as late as Friday, 4/26 when your phone is already on its way to your door. Thanks for your patience.