Give this thread a read. I spent a good hour answering this topic in it. http://www.hipforums.com/newforums/showthread.php?t=412026&f=67
Yoga is simply an attempt at a means to bring oneself in union from that which you’ve never been separate, it draws on thousands of year’s human trial and error, perhaps it’s best to start with a read on the Patanjali’s eight limbs originally outlined in the yoga sutra’s, the four main yoga’s one should become familiar with are: Jnana, Bhakti, Karma, Raja. Eventually one realizes the spontaneous cannot be made to happen, I am that I am, the world is that it is and life happens.