Firefox Profile Switcher Add-on

      If you are working with multiple profiles in Firefox you have probably your own ingenious way of launching them. Some Firefox users may use shortcuts to launch their profiles, others the built-in profile manager, the command line or an add-on like Switchy

If you are new to the concept, I suggest you take a look at the following guides that will get you started..."
Source: Ghacks Technology News
 Firefox Profile Switcher Add-on