Today RIM made PlayBook OS 2.1 available for Developers to download. Unlike the 2.0 beta downloads, 2.1 is fully featured.
You can head on over to https://developer.blackberry.com/devzone/register to register, or if you want the .bars for sideloading you can download them from http://jumbofiles.com/oshma1fjbdux courtesy of OSBB. Due to popular request, a version without some of the larger bars (still includes email, contacts, etc) can be downloaded from here: http://www.4shared.com/zip/3S3vTzNf/210560.html
Why would you want the .bars for sideloading you ask? I don't know why, but I've heard rumors that the Email app looks awesome on the BB10 Developer Alpha device.
Co-founder and legal nay-sayer of OSBB. Owner of SCrApps Application Development, WebWorks aficionado, Open Source contributor. SCrid2000 on most blogs. I build awesome BlackBerry apps when I'm not doing legal work or spending time with my wife and two boys.
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Check out my apps in BlackBerry WorldWebsite: SCrApps.org