i just finished reading The Summer King by OR Melling. It is EXCELLENT! A teen is asked to participate in a mission to help save Faerie (and that also might save her sister). The book is steeped in myth and legend both Faerie and Irish. Melling draws readers into the story in such a way to where one might become a believer in faries by the end.
Laurel doesnt believe in faries at the beginning, but her sister did. In order to begin her mission she is told to "Act as if ye believe and see what happens." I think I am going to start using that motto in my life. :)
I don't think this book is out yet but I got an uncorrected proof at the National Council of Teachers of English/ National Writing Project Meeting in Pittsburgh last fall. I am glad I picked it up. I plan to get some of her others now and check them out.
if you like young adult fantasy- pick it up!