I'm in Australia and can view them. Just type 'hotspot shield' into Google and the first link will provide you with a free program that generates a fake United States IP address cover for when you want to view 'US only' websites anywhere in the world.
The USOpen.org streams are still by far the best quality, but were buffering quite a bit yesterday for me. ESPN3 was 2nd best, but did not buffer nearly as badly.
If I recall, both of them took at least one day last year to get their quality up to peak performance. Hopefully today will be much better.
Still the best quality streams I've ever seen..