If you signed up to be a part of the Xbox LIVE Fall Preview program, it is now underway, so go and get busy.

A 25 character key is required to open and use the update, and all testers are under a non-disclosure agreement for the time being. According to NeoWin, the code will work on up to three Xbox 360 consoles.

While we don’t cover Xbox news as much as we might on TNW Microsoft, the Fall update is important enough for us to take a moment to discuss it. Included in the update, which was code-named ‘Madrid, is Bing search capabilities, a newly Metro-ized interface, YouTube integration, new content from some 40 partners, and voice recognition support. It’s a large package, to say the least.

According to Microsoft-prepared materials, once an approved user inputs their code, the updated dashboard and other features will not appear for some three to five days. This is what Microsoft has sent to those now in the program:

dashboardinvite 520x277 The Xbox LIVE Fall Preview is now underway

Microsoft closed the application process for the program some time ago, likely due to demand for inclusion driving more than sufficient sign-ups to provide the company with a workable testing pool. Given the installation lag, we do not expect much in the way of leaks until late this week, if not the coming weekend. Of course, at tips@thenextweb.com is always open to receive your, ahem, tidbits and screenshots.

The company did say, previously, to rejected applicants, to “stay tuned for future updates when the registration process begins.” That should be now. Get talking, Microsoft.

You can check out all our Xbox-related coverage here, if you want to poke through the archives.