Where to Learn backbone.js online
There is the primary site backbonejs.org where you get backbone. But the documentation is technical an is aimed at developers.
Here from YouTube is an explanation of “Why Backbone?” It is an excerpt of Lynda.com course “Up and Running with Backbone.js“
Thomas Davis has a good starting video tutorial on YouTube that is about an hour long. His tutorial site backbonetutorials.com has beginning, intermediate, and advance tutorials. And he has an eBook Backbone Tutorials on LeanPub.
CodeSchool.com has a course on Anatomy of BackboneJS (free at the time of this writing).
coenraets.org has a three-part tutorial on building an wine-cellar backbone app.