Lo all,
Mostly "because it was there", I decided to play with CUPS.
I've got a Brother DCP-770CW printer (about 4-5 years old), connected to my LAN via CAT5 - and my Windows PCs print directly to it. I'd also seen the Google Cloud Print (Beta) stuff (http://www.google.com/cloudprint/learn/) and spied a set of CUPS wrappers for my printer.
1) Login to OMV
2) Choose "Plugins"
3) Find and highlight "OpenMediaVault CUPS"
4) Click install
5) Wait 
That got CUPs installed, but printer drivers were still missing. The Brother website was as useful as a chocolate fireguard, as they only supply x86 drivers, and my N40L is x64....
So I had to :
6) apt-get install csh
7) Manually find & install (via dpkg) brother-lpr-drivers-common
Manually find & install (via dpkg) brother-cups-wrapper-common
9) Manually find & install (via dpkg) brother-lpr-drivers-extra
10) Manually find & install (via dpkg) brother-cups-wrapper-extra
So that's CUPs with the relevant drivers, but still no installed printer...
11) Then navigate to http://openmediavault:631/admin (login/password is the OMV admin one btw - that slipped me by!)
12) Click "Find New Printers"
For some reason mine was shown twice, so I just used the first one....
NOW you have a printer - and can choose to share it via Samba (I chose not to share mine as it's already mapped manually)
You may also need to add the printer to the OMV CUPs plugin page once it's in CUPs
Now for Google Cloud Print....
13) Visit http://dev.shyd.de/2012/01/rem…ebian-google-cloud-print/
14) Follow instructions 1 - 3, i.e. :
apt-get install python-pip python-cups
pip install daemon
pip install cloudprint
15) Follow the instructions to cut/paste the /etc/init.d/cloudprint file (and edit "myuser" to be "lp"
16) You'll also need to mkdir /var/spool/lpd and chown/chgrp the dir to be owned by "lp")
17) Follow the instructions to add the service and start it, and you'll probably get told you need to add python-daemon with a "-d" to get the daemon to work. Except it's already installed?
18) Run
pip install python-daemon --upgrade
apt-get install python-daemon --upgrade
19) You'll also need to get another package installed, to fix an error. I can't find it on it's own but running :
pip install distribute
...fixed the problem.
20) Now run /etc/init.d/cloudprint start
and you should be asked for your Google username/password....I can strongly recommend setting up 2 factor auth and application passwords, so you can disable the Cloudprint without changing all your Google passwords. But that's just me :0
21) Then go back to the Google Cloud print page (https://www.google.com/cloudprint?hl=en-GB#jobs) and you should see your printer
I've since installed a Google Android cloudprint app and can print to the house whilst on the move