Today the Tizen SDK for Wearable 1.0.0 Beta2 has been released and is available via the install manager or a SDK image for Ubuntu 32, Ubuntu 64, Windows 7 32Bit, Windows 7 64bit, Max OS X (Intel) and Mac OS X (Intel,CLI) versions. You can get it from the SDK download page.
Tizen SDK for Wearable is a comprehensive set of tools for developing Tizen wearable applications. It consists of the Tizen wearable IDE, Emulator, tool-chain, sample applications, and documentation. Tizen SDK for Wearable runs on Windows®, Ubuntu, and Mac OS® X.
More information can be obtained from the release notes. If you are developing a corresponding Android host application for Samsung mobile devices, you need to use the Samsung Mobile SDK in order to do this. We have also got an Introduction and Overview of the Samsung Tizen Gear 2 SDK, if you are not that familiar with it.