Icarus Camera Control - This is an open source program for controlling digital cameras, especially those that support PTP.
qDslrDashboard - Camera tethering as easy as 123!
digiCamControl - A DSLR camera remote control open source software Features:
Remote DSLR Control - Control your Nikon DSLR camera remotely from a computer.
gphoto - gPhoto2 is a free, redistributable, ready to use set of digital camera software applications for...
DSLR Remote Pro Multi-Camera - DSLR Remote Pro - software to control Canon DSLR cameras from a PC