When it comes to essential oils, I have been very overwhelmed with all the information I could find online when I started out using essential oils. Here is a small compilation of resources for you. I will keep on adding more as I evaluate them, and once I trust them, they will get added here.
Related to Essential Oils
The following organizations are dedicated to essential oils. They are brand independent and extremely science-driven. As an Aromatherapist that gets me very excited :-)
They also air on the safe side of essential oils consumption. A MUST for every Certified Aromatherapist.