There's no app for it specifically, but all you need to do is scan the images from your comic using a scanner app (many to choose from there, and one should be bundled with your Scanner itself), make sure they're jpeg and at a high resolution. About 150 to 300 dpi is best, then make sure they're labeled in page order (I.e. Page one is "1.jpeg") and then compress them with a .zip utility. This can be easily accomplished on the mac by selecting all the pics, right clicking on the selection, then selecting "compress # files". You'll be leftover with a file called "Archive.zip". Simply rename the first part to the comic's name and issue number, and then change the file type suffix to ".cbz". The computer'll ask you if you're sure about the rename, click yes. Now you have a comic book file that works with about 99.9% of comic reader programs out there.
From here I'd recommend getting a comic database app like "ComicBookLover". Think iTunes for your comic files: it saves covers, meta data, genres, sorts into series, etc. From there you can either read them on your desktop, or port them over to a mobile device such as iPad or iPod touch/iPhone and read them on the numerous comic viewers in the AppStore. I reccomend ComicZeal, as it has the most features, but there are other free alternatives like CloudReader.
Hope that helps.
~JYH
