Apple just opened up the WatchKit development platform to allow developers to get on board with creating apps for Apple Watch starting today. Apple Watch is expected to come in Spring of 2015 but Apple wants a robust app ecosystem for the wearable from day one.
The iOS 8.2 SDK beta including WatchKit is available immediately for iOS Developer Program members at developer.apple.com/watchkit. The WatchKit site includes programming guides, human interface guidelines, templates and more. Starting later next year, developers will be able to create fully native apps for Apple Watch.