Well I tried some manga, there's a .NET app on here that converts the JPGs into a PDF. Then I tried mobipocket creator from that PDF. I also tried the amazon conversion from the PDF.
The result is less than thrilling. The 4 shades of gray leads to the images not looking too great, but also beacause of the resolution/size of the screen the text isn't too readable.
That was just an initial test. I'm not sure if there's better ways of doing it that will lead to a nicer experience. ;-)