I believe both New Thought and New Age grow from the same idealistic principles, but they are two very different interpretations of these principles.  New Thought and its "Law of Attraction" is a very assertive Western idea, and it says that our thoughts are all important and can literally create reality.  The New Age, however, grows from the more Eastern interpretation of idealism offered by Buddhism and Taoism, which says that our thoughts are basically meaningless and we have no control in creating reality.  Responsibility, yes, but not control.  Although New Thought works have become popular and are heavily marketed to a New Age audience, I think it's pretty clear that they are two different and contradictory ideas.