PlayOn has closed their beta and released the streaming software for full release. PlayOn lets you stream Hulu, Netflix CNN, ESPN and may other online content sources to your XBox 360, PS3, Popcorn Hour and many other players. I use it with the SageTV HD200 which isn't officially supported by PlanOn, but does work for Hulu (not for Netflix unfortunately) and some of the other sources. I'm not a huge fan of the interface you get with PlayOn, but if you need Hulu, Netflix or the other streaming on your hardware, it's hard to argue against it.
You can pick up PlayOn for$29.99. They have plans for some new features and Wii support in early 2009.