The Linux answer from Scott Fritzinger and a lot of different developers to the growing need for Linux/UNIX digital camera software.
gphoto is a cool program for interfacing with digital cameras. As of writing, it supports 143 different cameras, and the number is growing. It supports all sorts of connection methods - serial, parallel, USB, IEEE1394 (aka Firewire®). Several frontends are also available. gphoto2 only comes with command line frontend by default, though. (You can only guess to which following frontends refer to: GnoCam, Kamera, gtKam... Innovative namings, yes? =)
Apparently gphoto is so good that some digital camera manufacturers ship it with their cameras!
The project's web page is at http://www.gphoto.org/.