You should be able to download these through your PS3 or through the web store.
they say they will only be available on the vita store (which is actually a different store than the ps3/pc one if you don't have a vita to see it) so we will have to see if they are actually going to stay true to that or not. I'm leaning towards they won't screw it up and that only people with a vita will be able to get them (which makes sense as it's a vita celebration)