AT&T has become the first US carrier to open pre-orders for the Samsung Galaxy S4, offering the 16GB White Frost or Black Mist variant in select areas for $199.99 on a two-year contract. The carrier says it expects Galaxy S4 orders to ship by April 30th, hitting mailboxes by May 3rd. Currently, only the 16GB model is available to order, suggesting AT&T will slowly open up pre-orders for the 32GB handset in the coming days. However, it comes just as AT&T begins shipping the HTC One, giving HTC a two-week head-start over its larger rival. Currently, AT&T order pages are experiencing some issues, so if you are unable to complete your order, we suggest you keep trying until it does.