Mangle to convert images for Kindle (May not work on iPad, special directory)
http://www.wired.com/gadgetlab/2010/08/you-can-read-manga-on-your-kindle-with-mangle/
Briss to crop PDF documents
http://www.freewaregenius.com/2011/03/24/optimize-pdfs-for-reading-on-your-kindle-3-crop-then-convert-to-a-kindle-friendly-format/