Address Book in Red

To use this icon, go to your Applications folder and right click on the Address Book icon. Choose Show Package Contents. Navigate to Contents>Resources. Replace AddressBook.icns with the new compass.icns. You should back up your old AddressBook.icns file before copying the new one to the folder. You can just change it's name. Restart the Address Book and your new icon will show up on the dock.

Of course, there are other ways to do this. You can use the Get Info then Copy and Paste method. I don't even know why I bothered with the other instructions... :-P