Packrat is a media collection manager application for Android. You can use it to add books, CDs, games, movies, etc. to your collection by scanning their barcodes and organizing them onto shelves. You can let Packrat organize your items into smart shelves, or manually stack items onto shelves of your own creation. You can also track items you don't have yet on a "wishlist" shelf.
getxbook is a collection of tools to download books from websites. There are tools to download from Google Books' "book preview", Amazon's "look inside the book", and Barnes and Noble's "book viewer". There is an optional GUI written in Tcl/Tk, and some shell scripts using OCR to create plain text or searchable PDFs and DjVu files from the downloaded books.