Comicscans.net is a great website for the comic book enthusiast. They offer many different comic book collections on DVD or for digital download straight to your PC.
A-Z Comics specialized in Golden Age comics in digital format. They are available on professionally packaged shrink wrapped DVDs with laser imprinted labels or on a portable 500 GB Hard Drive.
They are now giving away a full run of Captain Marvel Adventures Comics in digital format for the super hero lovers of the world.