There's an ethernet cable just itching to be used at my desk, but my mac doesn't recognize it for anything.
...and you've enabled the Ethernet connection in the Network System Pref?
Also, after you bring up the Network System Preference panel, make sure that
Network Status is selected on the "Show" drop-down. You should see a coloured dot next to Built-in Ethernet. If it's
green, you're good to go. If it's
red, then the network cable is not live (plugged into the wrong jack on your router?). If it's
orange, then your network connection is good, but your Mac is not getting an IP address.
I often get the orange status 'light' when I plug my Macbook Pro into my switch here at the office. I can get it to go green by simply disabling and re-enabling the connection. The easiest way to do that is to go back to the Show drop-down and select
Network Port Configurations. Uncheck the box for
Built-in Ethernet and click
Apply Now. Wait a few seconds, recheck the same box and click
Apply Now again. Now go back to the Network Status option, cross your fingers, and see if the status light for Built-in Ethernet turns green.
Now then, once your connection is up, seeing your shared folders from your PCs is as simple as selecting Network from a finder window. After a moment you should see your workgroup appear. Select that and you'll see the names of the PCs that have sharing enabled. Select one of those, then connect, type your login info (if needed) and select the shared volume. That volume will then appear as another mount on the left pane of the finder window.
Connecting to printers is equally easy.