Tizen 2.0 SDK and source code drops alpha, adds support for multi-window and more
The Tizen SDK runs on Windows, Ubuntu and Mac OS X.
source: Tizen (1), (2) via Engadget
UPDATE: Thanks to SamMobile, we have some beautiful screenshots of the Tizen 2.0 UI and it looks clean and "refreshing," probably not what anyone was expecting! Feel free to throw your 2 cents into the comment box.