Scott Kirsner has a list and ratings of the various movie download services. This is an immature market so far, but I believe that it's going to become the dominant way that we watch films at home.
Note which services are friendly to independents. It's a given that mainstream Hollywood films will be available. What's important is whether in the long tail world of the net there will be places for other points of view. I think that's animation's best hope for offering a wider range of content to audiences.