libgphoto2 is the core of gphoto2 software. It is a portable library which gives access to literally hundreds of digital cameras.
gphoto2 is the command line (CLI) interface to libgphoto2. It allows almost everything that libgphoto2 can do.
digiKam is an advanced digital photo management application for Linux, Windows, and Mac-OSX. The people who inspired digiKam's design are the photographers like you who want to view, manage, edit, enhance, organize, tag, and share photographs under Linux systems.
It uses libgphoto2 for importing photos and for capture.
Shotwell is a digital photo organizer that runs on Linux.
F-Spot is a full-featured personal photo management application for the GNOME desktop. F-Spot simplifies digital photography by providing intuitive tools to help you share, touch-up, find and organize your images.
Google Picasa has been ported to Linux using Wine which uses libgphoto2 for importing images.
Picasa for Linux
darktable is a photography workflow application: a virtual lighttable and darkroom for photographers: it manages your digital negatives in a database and lets you view them through a zoomable lighttable. it also enables you to develop raw images and enhance them.
It uses the capture abilities of libgphoto2.
Entangle provides a graphical interface for tethered shooting, aka taking photographs with a digital camera completely controlled from the computer.
GIMP is the GNU Image Manipulation Program. It is a freely distributed piece of software for such tasks as photo retouching, image composition and image authoring. It works on many operating systems, in many languages.
This software writes short movies with your digital DSLR camera Canon (R) directly to computer. The camera must have LiveView feature to work, like in Canon EOS 450D for example. The Program has preview, Av, Tv and WB control.
EOS Camera Movie Record
Stop Motion Capture animates a video from single frames. It uses your digi cam to capture these photos. Furthermore it contains various technologies, such as onion skin, bluescreen or export.
Stop-Motion Capture (german)
Java bindings for Linux gphoto/gphoto2 library.
gphoto2 java bindings
The site provides python bindings and some sample for libgphoto2.
gtkam is the old GTK2 reference graphical front-end to libgphoto2. It is not maintained currently (volunteers welcome).
gphotofs allow you no mount your camera on Linux based on the FUSE technology.
gphoto 0.4.x is the old fashioned version of gphoto software. It is not longer being maintained.