What is Tizen?
Tizen is a free and open source mobile operating system. Tizen is based on the Linux operating system and sponsored by the non-profit technology consortia Linux Foundation and LiMo Foundation. Tizen was born out of MeeGo, which was itself a combination of the mobile operating systems Moblin, created by Intel, and Maemo, created by Nokia. Development is currently led by Intel, Samsung, and some former MeeGo developers. Although Tizen is intended to replace MeeGo, the MeeGo codebase remains available and its development continues in the Mer project. [read more]
In summary,Tizen was developed by Intel to replace MeeGo, its development is in progress and going pretty well as the first screenshots have surfaced:
these were taken from a samsung phone, and it is resonable to say the first tizen phone will appear during this year's MWC (mobile world conference).