Android: FBReader is a snappy ebook reader for Android phones that, when combined with a free Dropbox account, becomes an effortless ebook synchronization tool.
Lifehacker reader WordTipping highlights how he synchronizes his ebooks using FBReader and Dropbox:
Android ebook reader FBReader makes a great team with Dropbox. Why? Because FBReader lets you specify where on your SDCard your ebook library is located. So, just store your ebooks on Dropbox and you will always have access to them easily without any fuss.
FBReader is a free ebook reader for Android phones with support for ePub, FB2, and OEB—future releases will include support for the additional formats FBReader's big brother, a desktop application, supports. Download FBReader by searching for "FBReader" in the Android Market or scanning the QR code to the right. Thanks WordTipping!