I am printing in Letter / US letter format with KDE. CUPS is configured in Letter (that's what I see in my /etc/cups/ configuration file.) But it always comes out in A4. I believe the KDE printer manager overrides all my US settings for some reason. I try to modify the driver settings in KDE print manager which seems to be locked on A4. But when I save it or try to test print, it asks for name /password to save the settings. I can never save under my regular user's name and password (I can only enter root) and when I go back into it later, it is set, yet again, to A4.

I'm using KDE 3.4.2 Level "b", from Suse 10.

Thanks a lot.

Open a terminal, log in as root and then type kcontrol. This will start up the kde control panel in root mode so you can tweak the Peripherals/Printer settings.
One of the settings is to add "Allowed Users" where you can add your user name (presumably resulting in the ability for you to change settings at a later time without having to become Administrator).
(Once set up I've not had to go back and tweak the settings a 2nd time).

There's also a Printer entry in Yast/Hardware. Don't know whether there's paper settings there or not.

An alternative is to configure CUPS through its Web interface. Open your browser and type http://localhost:631 as the URL. This should take you to the Web-based CUPS configuration screen. Click "Do Admin Tasks," type in your root password, and press "Configure Printer" under the printer you'd like to configure.