Virtualization Experts Series continues with Live Storage Migration explained by Brian Lewis.  This step by step article shows the how, why, and what of moving virtual machine disks from one physical location to another, and the Powershell command is thrown in as well for you scripters out there.  Take a look:

http://mythoughtsonit.com/2013/03/step-by-step-storage-live-migration-part-8-of-20/