Marvel (Comics) API - Create awesome stuff with the world's greatest comic API
Sequential - Sequential is an image viewer for Mac OS X.
DC Universe - The DC Comics streaming service w/ original content
CDisplay Ex - CDisplay Ex is the most used comic book reader.
Comixology Unlimited - Netflix for comics and graphics novels by Amazon
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!