Andrea Butje, a Clinical Aromatherapist at Aromahead Institute School of Essential Oil Studies offers excellent webinars and courses on the use of essential oils. See more at: aromahead.com. She has a free introductory course that includes some good DIY recipes for your home!
The NAHA (National Association for Holistic Aromatherapy) is a great resource. http://www.naha.org. NAHA also lists trusted Certified Aromatherapists and industry experts.
I also trust Wellness Mama at wellnessmama.com. I love her site and have made a ton of her recipes. She uses EOs daily, but focuses on quality oils and does her research first.
For information on safely using essential oils during pregnancy, Stephanie Fritz, The Essential Midwife is a great resource. http://www.theessentialmidwife.com.