Xiphos: Xiphos is a Bible study tool written for Linux, UNIX, and Windows using GTK, offering a rich and featureful environment for reading, study, and research using modules from The SWORD Project and elsewhere. It is open-source software, and available free-of-charge to all.
OliveTree: Olive Tree Bible App works seamlessly across your Mac, PC, iPad, iPhone, and Android phone. Take notes, highlight verses, bookmark your favorite passages, and watch them all sync automatically to all your devices.