iReader Review has an article on the Kindle 3 and Manga. They have lots of screen shots and also go into great detail about how to get Mangle up and running on the K3.
The Kindle 3 handles images really well – But can Kindle 3 handle Manga?
K and 4rc wanted to find out about Kindle 3′s Manga capabilities and also how well Mangle, the Manga Program for Kindle, works with Kindle 3. Well, this post has some photos to show you that Kindle 3 does fine – The Kindle 3 Manga photos are after the jump (second part of the post). …
Overall, Mangle lets you view Manga as Manga books on your Kindle 3 easily and well. It’s just like reading a book since your place in the Manga and your settings are preserved. The ability to zoom in a lot means you can read the text even if it’s too small and you can also zoom into individual frames.
It should be noted that the prime purpose of this is for reading scanlations – illegal scans of manga. You could argue fair use however (lets say you scanned the manga yourself).
Is there anywhere to buy commercial manga in electronic form? I’d be interested in buying some if there is.
You can also use a great program called Calibre.
http://www.accessj.com also has good guides on studying Japanese on the kindle, and buying and reading Japanese eBooks.
There is more powerfull and optimised version of mangle: https://github.com/proDOOMman/Mangle/downloads
It can into cropping of white corners, multithreading, reading and writing into cbz and so on