It turns out it doesn't. Indeed, the FAQ clearly states that downloaded movies and games are "like a DVD" in that they allow a single download and cannot be transferred to any other devices (except for a limited number of PSPs), including a second PS3 should the first die or the same PS3 should the original 20 gig harddrive fill up and old movies need temporary shifting.
Also of note is that the PS3 movie store does not sell HD movies, the SD movies cost much more than buying from local stores, and the SD and HD rentals cost more than renting locally as well. I can't imagine the kind of thought that went into this kind of shit. Wait, yes I can.
Young, chipper Sony exec: Hey, the guys at Steam and Xbox Live have something cool with download services. We should do that--except also offer a vast selection of movies, since we're a whole media center and not just a console! Cool, right?
Codgerly Sony exec who wants to retire: Sure, whatever. But to make up for ease of use, we'll charge more than local stores would and only allow a single download of nontransferrable content.
In conclusion, fuck Sony and I'm never buying another thing from their Sean-damned store again.