First up, House of the Star by Caitlin Brennan, aka dancinghorse. I must admit I'm biased towards this book 'cause the cover pony, Pandora, is in my backyard. :>) And see the horse in the icon? Made that this morning in a horse-shaped pan from Ikea.
sartorias also wrote a lovely post about the book, Horse Girls and Magic.
My good friend Pearl North, aka annesible: The Boy from Ilysies, which is the sequel to Libyrinth.
Congrats to both! Y'all run out and buy them now!