WARNING: This plugin is not created my VMware, so us at your own risk and test it out first before you try and use it in Production.
You can get a GUI Storage VMotion plugin for VIC 2.5
You can download this plugin at http://code.google.com/p/akutz/downloads/list
This plugin acks as a normal VMware plugin (ie update manager, etc)
All you do is right click your VM and you will have move storage option at bottom, then drag the VM to a new datastore of your choose.