Applications are now able to access SteamVR hardware using the new OpenVR SDK. The SDK is available for download here[github.com]. It provides support for the HTC Vive Developer Edition, including the SteamVR controller and Lighthouse. See the release notes[github.com] to learn what has changed from the Steamworks VR. The SDK also includes new documentation[github.com] and samples[github.com].
Along with the OpenVR SDK support has been added to support Unity via the SteamVR Unity Plugin and native SteamVR support in Unreal 4.8. Both will be available soon.
This SDK release is the next step toward the first major Developer Edition shipment. If you have not yet applied to receive a Developer Edition, there is still time.