I need a driver for a Dell Photo 926 Printer

Unfortunately, there is no official linux driver from Dell for this device.

However, the device is actually a Lexmark printer -- dell do not make printers, just repackage them.

So it is apparently *possible* to install the lemark driver -- but not easy, as lexmark have stuffed up their installer.
http://ubuntuforums.org/showthread.php?t=798188

heres how:

Press Alt+F2 then type "gedit" (without quotes) to open the text editor. Cut and paste the following into the text editor, then save the file to your home folder (eg /home/ned/ , or /home/nedplace/ , or whatever corresponds to your ubuntu username) -- call it "install-lexmark.sh".

Now, open the file manager, and find this file (install-lexmark.sh). Right click it, select properties, then permissions, then tick the box labelled "execute". Now press close.

Now open a terminal by pressing Ctrl+Alt+T, or by selecting the terminal from the applications menu.

now type ./install-lexmark.sh

This will run the script and attempt to install your printer. You MUST be connected to the internet for this to work, as it will download the components it needs in order to complete the installation.

I have only tested this on a 64 bit machine -- I believe it will work on a 32 bit one, but cannot test, as I do not have that hardware.

-- CUT BELOW HERE! ( DO NOT CUT THIS LINE) --
#!/bin/bash

#64 bit system test -- we need to install stdc++5
if [ `uname -m` == "x86_64" ] ; then
       # this driver depends upon libstdc++-5; so download the old stdc++, unpack and symlink it
       wget "http://security.ubuntu.com/ubuntu/pool/universe/i/ia32-libs/ia32-libs_2.7ubuntu6.1_amd64.deb"
       dpkg-deb -x ia32-libs_2.7ubuntu6.1_amd64.deb ia32-libs
       sudo cp ia32-libs/usr/lib32/libstdc++.so.5.0.7 /usr/lib32/
       pushd .
       cd /usr/lib32

       sudo ln -s libstdc++.so.5.0.7 libstdc++.so.5
       popd
else
     # 32 bit, we can just install libstdc++5, at least as far as maverick
      sudo apt-get install libstdc++5

    if [ $? -ne 0 ] ; then

         echo "Problem installing libstdc++5; giving up."
        exit 1
    fi
fi

wget "http://downloads.lexmark.com/downloads/cpd/CJLZ600LE-CUPS-1.0-1.TAR.gz"
mkdir lexmark
mv CJLZ600LE-CUPS-1.0-1.TAR.gz lexmark # move the package to a folder. optional, but recommended.
cd lexmark

tar -xvzf CJLZ600LE-CUPS-1.0-1.TAR.gz # extract the driver.
tail -n +143 z600cups-1.0-1.gz.sh > install.tar.gz # the sh script is broken for newer systems. use `tail` to extract the binary portion of the script.
tar -xvzf install.tar.gz # extract the contents produced by tail
sudo apt-get install alien
alien -t z600cups-1.0-1.i386.rpm # convert unusable rpm packages to tgz.
alien -t z600llpddk-2.0-1.i386.rpm # convert unusable rpm packages to tgz.
sudo tar xvzf z600llpddk-2.0.tgz -C / # extract the tgz's to / putting the files in their right place
sudo tar xvzf z600cups-1.0.tgz -C / # extract the tgz's to / putting the files in their right place
sudo ldconfig # DO NOT SKIP THIS STEP or your printer backend won't find required libraries
cd /usr/share/cups/model
sudo gunzip Lexmark-Z600-lxz600cj-cups.ppd.gz # unzip the ppd, which should _not_ be gzipped
/etc/rc2.d/S19cupsys restart

cd /usr/lib/cups/backend
./z600
-- CUT ABOVE HERE! ( DO NOT CUT THIS LINE) --

Note that I have also not tested this on your printer -- I don't own one. I just know that it installed the driver, not that the driver works.

Finally, i should attribute the script location (which I modified):
http://ubuntu-art.org/content/show.php/Lexmark+driver+pack+for+ubuntu?content=98648