Cyanogen recently announced their plans to bring an installer for their custom Android ROM to more phones by putting it up on Google Play. they have made good their word and done so. So, if your device is listed as compatible and you want to given it a shot, do head over to Google Play to download the installer.
Supported devices include:
Samsung Galaxy S II, III, and 4
Samsung Galaxy Note I and II
Nexus S, 4, 7, 10
Samsung Galaxy Nexus
No; you do not need to root your device, but you do need a desktop application to execute the installation.