The Open Cloud Computing Interface (OCCI) working group is scheduled to kick off this week following approval by the Open Grid Forum (OGF) steering committee last week. While completely independent of the Open Cloud Initiative, the two projects share similar goals and the API should be one of the first to be whitelisted by this project.
It will allow users to manage the lifecycle of a machine across various implementations of cloud infrastructure and will constitute the first "real" cloud standard when an implementable draft is available next month. That's right, we're going for the world speed record too, but that's ok because we've already done a heap of background work and research into existing implementations. Other similar APIs include Amazon EC2, Sun Cloud APIs, ElasticHosts and GoGrid APIs.
With widespread industry support already it constitutes a significant step towards an "Open Cloud".