I like using usps priority mail flat rate boxes if the buyers are paying with paypal. I honestly dont ship internationally, unless I can get some sort of tracking or delivery confirmation (which is NOT available on every usps international shipment depending on country). I have been stung before by buyers who file paypal claims against me after not receiving itemns, and I cannot confirm if they ever arrived due to not trackable shipping.
Ebay also has an excellent international shipping program for sellers. You ship it to their shipping center. They then repackage it and assume all liability for the package arriving.
Maybe Im just paranoid tho. Now that paypal buyers have 6 months to file claims.....I dont think exposing myself to that kind of liability, especially with countries that have terrible postal services.