1) Music on the audio book is by The Gothic Archies (featuring Stephin Merritt). The Gothic Archies has been described as "The Magnetic Fields with every spark of hope extinguished" although not by me. The HELLO CD of the Month club Gothic Archies CD was how I discovered Stephin Merritt in all his incarnations, and is still one of my favourite things. The song the rats sing will be up on the website, although you'll need to buy the audio book (read by me, 3 CDs or 3 cassettes) to hear "You're Not My Mother And I Want To Go Home."
2) There will be promotional marbles. Honest there will. Three of them in a promotional marble bag. Going to stores and librarians and so on.
3) A very limited 500 copy signed edition will be made available to retailers through Diamond Distributors. I'm not sure what the qualifications will need to be for a store to be able to get one -- probably ordering a certain number of copies of Coraline, or of backlist titles or something. The limited book will have some unused Dave McKean artwork (including his first cover design -- which he didn't like, so he did another the following week, which is the one we're using) and some other stuff, including some reproductions of handwritten manuscript pages. It's not going to be available through regular bookstores, only places with Diamond accounts, and is being done by Harper in association with Diamond.