Essential Oils

I'm looking for information on essential oils. I know about some of them, like jojoba and rosemary, but I want to dig deeper to find what other oils are out there and what they do. So far, the best information that I've found has come from Esoteric Oils. It includes information about various oils and gives a couple hair care recipes. The info is not limited to hair care; there are links about alternative medicine and treating various ailments with oils.

Please note that I am not endorsing anything sold by Esoteric Oils, nor have I tried any of their products/recipes. This is just the most comprehensive list that I have found to date. If any of my readers know of other sites (or better yet: books!) that provide information on essential oils, please hit me up in the comments or via email. I'd appreciate it soooo much!