Awesome e-book management, calibre (formerly known as libprs500)
If you've got a Sony Reader, and don't like Sony's book management app (or you don't run Windows) you should definitely check out calibre. It lets you manage your ebook library, convert files to the Sony Reader format, tweak metadata about your books, manage the books on your Reader, preview the books. It will even download some newsfeeds and put them on your reader. It's open source, written in Python and runs on Windows, Linux and Mac OS. It also contains command line apps to do format conversions and to transfer books to the Reader. It just plain kicks ass.
NOTE: libprs500 was recently renamed calibre. Different name, same awesome app.
