Samsung and the Tizen Association have today the Tizen SDK Wearable published. This apps for the new Samsung Smart Gear Watches and future, similar devices on Tizen base can be developed. The approximately 550MB large download includes, inter alia, to also test an emulator for the apps also equal to having to own a Samsung Gear without it. The finished apps can not be uploaded to the Tizen AppStore interestingly, but are Samsung's own store SamsungApps distributed.
The download and many more useful information finds you here and here.
