For complex application, an idea of distributed synchronization mechanism should be implemented. Especially in the case of Enterprise Applications, one would very often need one of N roles to take ownership of a resource (e.g. as a Master Role).
I've just published a couple blog posts about this, and I'm expecting to do another one soon specifically about leader election. See http://blog.smarx.com/posts/managing-concurrency-in-windows-azure-with-leases and http://blog.smarx.com/posts/building-a-task-scheduler-in-windows-azure