Yes, you can add a new address during checkout and have an order shipped to the US.
We have discontinued USPS first class shipping for Canada and for International orders.
Shipping first class with the USPS was costing us so much in terms of lost product that we simply could not continue. We were having shipping times of 2-6 weeks, which left our customers extremely frustrated. And without any kind of tracking or recourse, there was absolutely nothing we could do.
We are now shipping FedEx whenever possible so that you'll get your products in a timely fashion. Most orders should be received in as little as 7 business days, and sometimes even more quickly.