You can find more up to date instructions for
Couchbase Server on Azure in Step by Step Guide
Today at TechED europe, Azure released the new Marketplace experience. With the new marketplace, it gets easier to deploy Couchbase Server on Azure. You can pick up one of 2 options: Couchbase Server 3.0 with Silver or Gold Support package. You can find more details on the support options here.
For those of you deploying to Azure, you can also follow the best practices discussed on this online talk we did a few weeks ago with folks from Azure – Rafael and Jeremiah.