Microsoft on Codeplex released a set of ACS cmdlets which wrap the management API of the Windows Azure AppFabric Access Control Service.
"You can use those new cmdlets to save repetitive provisioning processes in form of PowerShell scripts, and consistently reuse them just by passing as parameters the targeted namespace and corresponding management key. You can use them for backing up your namespace settings on file and restore them at a later time, or copy settings from one namespace to the other. You can easily integrate ACS management in your existing scripts, or even just use the cmdlets to perform quick queries and adjustments to your namespace directly from PowerShell ISE or the command line. In fact, you can do whatever you are used to do with PowerShell cmdlets."
There's just 23 of them, and we might shrink them further in the future.
All cmdlets support get-help including the -- Full option, although things are not too verbose at the moment: in subsequent releases we'll tidy things up, but we wanted to put this in your hands ASAP.
You can dowload cmdlets from the CodePlex site.