The majority of the digital publishing venues sell internationally. (Amazon, Nook, Apple, Smashwords, Kobo, etc.)
And most of traditional publishers do sell globally. If that's the route an author is going, he/she needs to check contracts because often the royalties are different for books that are translated. If the author has an agent, it's part of their job o get the best deal for a client, which includes foreign rights/royalties.