Yeah i can probably give you some help. I have a Powershot a70 that I have managed to get working.
Most of this is from: http://www.gphoto.org/doc/manual/permissions-usb.html
host:~# /usr/lib/libgphoto2/print-usb-usermap >> /etc/hotplug/usb.usermap
NOTE: The instructions initially say to do:
host:~# /usr/lib/libgphoto2/print-usb-usermap > /etc/hotplug/usb/usbcam.usermap
but that didn't work for me on RH9 so I had to do it the other way.
Choose the right /etc/hotplug/usb/usbcam script for you. These are found in /usr/share/doc/gphoto2/. You have some choices. You will probably want either usbcam.group or usbcam.user. With the group file you create a group that should have access to the camera and then add all the users you want to allow to that group. In my setup I have used this one and left the group as the default (camera) and added my users to the camera group. With the user file you give access to just one user. You will need to modify either file to use the group/user you want. This file should be copied to /etc/hotplug/usb/usbcam (NOTE: usbcam is the file name you are actually doing a copy and name change here) and be made executable.
At this point things should work. If you went the group route you will need to logout and back in for the changes to take affect. You should be able to plug your camera in and turn it on (NOTE: it must be in picture view mode not picture taking mode). I suggest watching the messages file when you turn it on (tail -f /var/log/messages) to insure you don't see any errors. You should see it notice your camera and load it up.
You can then do:
alice@host:~$ gphoto2 --list-ports
alice@host:~$ gphoto2 --auto-detect
alice@host:~$ gphoto2 --summary
alice@host:~$ gphoto2 --list-files
alice@host:~$ gphoto2 --get-all-files
Or alternately use gtkam or what have you.
The only issues I have had are:
1. If I hit a corrupt file the camera is no longer recognized.
2. After one use the camera is no longer recognized.
The solution to both problems seems to be a system reboot. This generally ticks me off but as of yet I haven't found a solution.
Sorry for being so long but I hope that helps.