There are a lot of parameters that need to be met for importation, mainly depending on where from. In certain circumstances all that is needed is that the seller in the country of origin must obtain export papers, and everything on your end works as a basic shipment, except it must be run through U.S. Customs and the Department of Agriculture and U.S. Fish and Wildlife. I believe one official can usually take care of all three.
In certain circumstances you will also need to acquire permits for imports. Usually the easiest route here is to find someone who allready does importing, and hire them as a broker for you.
All of my animals I have had imported were through brokers and friends. I had 1.1 Western Costa Rican B.c.imperator, 2.2 Panamanian B.c.imperator, imported from Zoos in Costa Rica and Panama, they went through a broker and a friend of mine. I bought a Leopard Boa from Hans Winner in Germany and Hans sent a large shipment out to Mark Bell in Florida so that all customs checks etc. could be done at once for a reduced fee, and then Mark shipped me my Leopard.
If you email me chris.gilbertboa@gmail.com, I can email you .jpg copies of the CITES export papers from my Costa Ricans and Panamanians, so that you can see what they are.