There are 2 customs forms in the US. There's a short form for things 4 pounds or less, and a longer form for things over 4 pounds. I believe both are now printable online using this linkDo any of you know if one can just do a customs form on the web site and if so how to navigate to it?
https://cns.usps.com/go/ShippingInformationAction_input
[still working on 24 Jan 2014]