Google announced on Tuesday Android Wear, which is primarily a way to carry Android through to wearable technology (namely, watches). There's a Developer Preview available now for those with Android Developer accounts who are serious about learning more on Android wearables, but developers will have to wait for an software development kit (SDK).
Google's Android Wearable Concept
Motorola has already blogged about the Moto 360, which will be available "Summer 2014 in a variety of styles." On the official Moto 360 site a number of images are shown of an Android concept watch in action. It displays the weather, meeting reminders, or GPS navigation, aside from the screen that displays a watch face.
Currently there's no official SDK (software developer kit) to build new apps, but the Developer Preview will let you test your existing apps and "see how they will appear on square and round Android wearables." There's a list of partners at the bottom of the Developer Preview page, and all of them are technology companies except Fossil, a watch brand.
Here is the video Google released showing the developer preview in action: