Open System Preferences->Keyboard Pane, Input mini-tab and put a checkmark in 'Show Input emu in menu bar' the quit system Preferences. Then when it appears in you finder's menu bar click onto it to 'Show Character Viewer'. When Character View open highlight the Letterlike Sysmbols and select the copyright symbol!
Plus if you hold the keyboard keys: Alt key and hold it down and hit the letter G to place a copyright symbol like this: ©