Heres where I got mine (shocked I got it before official release):
http://www.chapters.indigo.ca/books/...er+sunset%2527
But for the States Amazon is probably best:
[ame="http://www.amazon.com/Just-After-Sunset-Stories-Collectors/dp/1439115303/ref=sr_1_1?ie=UTF8&s=books&qid=1225934420&sr=8-1"]Amazon.com: Just After Sunset: Stories (Collectors Set): Stephen King: Books[/ame]