Amazon Kindle Store sells .AZW ebooks protected with DRM. To read ebooks from Kindle Store on a
Nook or Apple
iPad, you need to remove DRM protection from .AZW ebooks and then convert them into EPUB. You can do both (drm removal and EPUB conversion) using freeware
Calibre.
Download freeware Kindle DRM removal plug-in for Calibre as well as standalone Kindle DRM removal software:
ebook DRM removal tools archive.