Here comes Google Tag Manager!

Google Tag Manager, a free new tool from Google that helps you organizes all your tags into one slick piece of JavaScript code.

Google Tag Manager allows you to enter all your tags in one location. You define on which page or pages a particular tag should appear and the magic of Google does the rest. This is particularly useful if you manage more than one site that each uses multiple tags.

You need to create a new Tag Manager account to use it. Despite needing a new account, you still will need all your other Google accounts like Analytics, AdWords, and the like.