Preorders were scheduled to go live at 11AM EST and only last for one hour, but there was an unknown issue that caused a delay. In order to make up for that delay, OnePlus has extended the preorder window for the One to two hours, and the timer began at noon EST, meaning you have until 2PM EST to get your order in.
We should note that we haven't been able to get a preorder through. Each time we try to go to the actual order page, we are getting an error saying "Not a valid OpenID". So, this preorder obviously has some issues to deal with. If you are able to get through, you should be able to order a maximum of two OnePlus One handsets, and payments must be made through PayPal.
Let us know if you have success ordering.