eBay enrolled me in it automatically. I'm in the US. International sales get shipped to an intermediary (mine have all been in Chicago) and payments go through on the normal schedule. Once I had a package to Bolivia go missing and eBay covered it. I imagine it works similarly elsewhere. No need to fill out customs forms or complicated shipping.
I regularly buy from Japan and China on eBay with no problems. I've also bought from Germany, Spain, Slovenia, Czech Republic, UK, and Canada. Again with no problems beyond ordinary.