- Download and install Kindle for PC. Sign in, download the books you want.
- If your books are DRMed (and many are) then you will need to DeDRM them. MobileRead policy forbids giving in-depth guidance on this matter
, but we are allowed to suggest you google "apprentice alf" for more details
.
- From calibre, open the Add books dialog, and import your books from the default location at
Code:
C:\Users\<username>\My Documents\My Kindle Content\
- Install the iOS reader applications and Marvin XD plugins for calibre.
- Send books directly from calibre to Marvin.

The legality of doing this depends on who you ask. The publishers think it is horribly illegal since you don't have to pay them for the same book twice

-- others

think it is legal according to the Fair Use Doctrine.