The Hyperspace section of the official Star Wars site has a Star Wars Episode III webdoc which details the workflow involved on the HD tapes: from filming, to logging, editorial, sound design and the VFX work of ILM. Director George Lucas, Editor Ben Burtt and Animation Supervisor Rob Coleman, among others discuss specific stages of the process from start to ILM finals.
The webdoc shows on monitor screens the work in progress of one of the lightsaber fights in the film. Rob Coleman discusses some of the digital doubles and head replacements. You can watch the webdoc here: