For those of you who may be registered windows phone developers, you may be getting invitations to download a beta version of Mango for your device. The process also involves a lengthy document of instructions (which they need you to follow to the letter), a new version of Zune for your PC, and agreeing to backup your phone, and actually backing it up. The last part is especially important as Microsoft is saying that you won’t be able to go directly from the Beta to the full version of Mango, but you will have to go back to your backup first.
For those not sure what they might be getting with Mango or what changes are coming, there were 4 videos / review posts a few days ago, which you can see here, and Engadget now had a lengthy overview of Mango including videos of some of the new features.
Microsoft say they are working on a better distribution chain to upgrade all of the developers to Mango which will come along shortly, but in the meantime, it is invitation only.
However, in addition to Mango being available for your phone, Microsoft now has a second beta of the SDK out (called, Windows Phone SDK 7.1 Beta2), and that is available to everyone from the Microsoft Download Center.
You can get all the juicy details at The Windows Phone Developer Blog.