Why is it free now?
It has been said that "this decision was made in light of Toshiba's recent announcement that they are discontinuing their HD DVD business. The reasons for offering the emulator for free are two-fold.
Microsoft is committed to interactivity and giving content authors the ability to create more compelling entertainment experiences. The specification for HDi was developed with significant input from studios like Warner Bros. and Disney based on scenarios they desired in the next generation format. Offering the emulator for free allows a greater audience to experiment with interactivity with little to no cost.
"Second, the emulator beta program had approximately 80 participants across the industry who relied on the emulator for testing HDi content. Continued access to the emulator will assist those post houses and developers in completing their outstanding HD DVD projects."
What can you do with this?
"The Xbox 360 HD DVD Emulator allows you to run complete HD DVD projects - video, audio, and advanced interactivity - on your Xbox 360 from an external USB drive or networked PC. Once you have your project looking just the way you want, you can burn it to a DVD-9 and share it.
A quick Google search will turn up a slew of uses and programs to make use of the emulator for the ambicious. How very...kind of Microsoft...