Mythago's right. With the Fey, you have to remember they are far above the ways of men. It doesn't work very well with DnD, where elves and such are on the same footing as men. The Tuatha de Danu might be powerful enough to be considered demigods, as would the Unseelie Host. Games like Ars Magica, Exalted, Castle Falkenstein, among others do a better job of reflecting the nature of the relationship between fey and mortal because they were designed to do that, rather than put men and fey on equal footing.
Still, if you are willing to go outside the d20 lexicon for information, there are plenty of resources.
Katherine Briggs, IIRC, has written several books on faeries. Good solid ones, not the glorified coffee table books so common now.
Ars Magica should have plenty of info. I second the Faeries recommendation there.
Castle Falkenstein had Lord Auberon's Guide to Faeries, which has a ton of info about the fey, Seelie and Unseelie courts, and how they interact with mortals. It was written by Jeff Grubb, of 3e fame.