Update: Sony, which makes the rival PS3, is not allowing movies from Sony Pictures to be streamed through the Netflix service to the Xbox.

Adding to the options of streaming movies to your PC, Mac, or TiVo, Netflix now streams 12,000 movies to the Xbox360. That includes 300 HD movies.

Xbox watchers have been waiting for this since last July. Add the Netflix streams with the Xbox 360′s Live Party feature and you can watch a movie with your friends remotely.

Bringing Netflix streams to Internet-connected devices is part of CEO Reed Hastings’ overall strategy. At the NewTeeVee Live conference last week, he talked about the need ultimately for browsers to become TV-capable. From NewTeeVee editor Katie Fehrenbacher’s notes of his talk:

We need web browsers — Explorer, Firefox, Safari, etc. — to play web on televisions. People tried it 10 years ago without success but that was in the age of low-speed dial-up. Today for the web-on-TV experience to begin we need broadband, high-def screens, and a pointer remote. The video game generation is quite comfortable with using a pointer on the TV.

Starting at CES next year I see breakthroughs for the web on television. The logical start is video game consoles — the Wii is so close, but we need high-def and to support modern codecs. Also built into televisions we’ll have Internet tuners. The issue with that is that device makers don’t want to bet too big on too-advanced tech, because then they could bet wrong on big devices. Web video will continue to grow, nurtured by PC and laptop-based ecosystem, then will expand to web browsers on the TV screen.

That web browser for TVs sounds like Boxee.