Remap Copy and Paste shortcuts on a Mac

Go System Preference > Keyboard > keyboard shortcuts and set Application Keyboard Shortcuts > All Applications

Add shortcut

Copy ^C

Undo ^Z

Cut ^X

Paste ^V

Select All ^A

Done :)

You could try to map Command to the Control key, and vice-versa. It's much easier to do and, in my opinion, is almost identical to Windows keyboards.

Just go to System Preferences -> Keyboard & Mouse -> Keyboard. On the lower left side is a button, Modifier Keys... Just switch Control and Command around.

I was able to get this to work by using a combination of DoubleCommand and jtbandes hint from here. First check the function key acts as control key box in Double command. Then save the file ~/Library/KeyBindings/DefaultKeyBinding.dict with the contents

{"^c" = "copy:";}
{"^v" = "paste:";}
{"^x" = "cut:";}

After you logout and log back in you should be able to use fn-c to copy etc. There are obvious drawbacks to this approach. You have to explicitly define every command you want to use fn for and mapping to control and then fn is really hacky. Unfortunately I wasn't able to get it to work another way. At first I thought you might be able to select both the "command key acts as control key" check box and the "fn key acts as control key" but that didn't seem to work. Ditto for changing to control with Alex's method above. I was also unable to find the modifier for assigning commands to fn, and Apple's documentation seems to indicate that it's done at a lower level than keybinding has access to. If someone knows a better way of doing this I would love to see it.