Ask HN: What is required for a Danish citizen to work in the US for 6 months?

I have a friend from Denmark. He wants to come and work here as a software engineer in the US later this year, as a sort of intern, starting August or September, until his next university semester in February. I don't know a lot about this subject, but my first inclination was to explain to him that he can't work here without getting a company here to sponsor an H-1B visa for him. Firstly, is that true, or is there another way? Secondly, do you know of any companies that sponsor such pieces, or if there is an online resource for finding such companies?