There aren't yet but there are some in the works coming out over the next few months. One is suposed to follow Vader immeadiately after ROTS...but I can't remember what its called. There was an article about it on starwars.com a while back. They said Labrynth of Evil, the ROTS novel, and this new book will form like its own little trilogy that SERIOUSLY detail Anakin's fall and the aftermath. Should be pretty good.