I'm new with Linux and I've managed to get a good start with this OS (I installed knoppix).

I recently got my printer/scanner/copier to work (lexmark x75), except now I want to change the preferences so that I don't waste the inkjet. can anyone help me to change the options on the printer so that it only prints black and white, instead of printing in color. Step by Step instructions would be strongly appreciated.

I believe both kde and gnome have pretty good printer configuration utilities where you can set up the default options. If you're using CUPS, you can also set the printer defaults via web browser, by pointing the browser to the address http://localhost:631 and entering "root" as user (plus root's password) when asked.

There's also a GUI frontend for configuring CUPS, called xpp (X Printing Panel). To use xpp (once you've installed it) you can rename /usr/bin/lpr to something like /usr/bin/lpr-orig (so that you can return it if you change your mind) and then make a symbolic link from /usr/bin/xpp to /usr/bin/lpr. After these procedures, xpp should pop up before the actual printing starts so that you can change the printer settings. Notice that xpp only works with CUPS.