I've been pursing the Kindle app story ever since the first pair showed up in the Kindle Store. I've pestered Amazon with questions, and when third party apps showed up I pestered their developers. I think now is a good time to share what I know.
That's it. That's all I know. I'd really like to be able to give you some background info, but I can't. Amazon have tied down everyone with some pretty scary NDAs. No one is talking, and even if someone gives me some information I won't be able to share it (it might get traced back to them).
If you want to know more details like when we'll see more apps or when the actual app store will launch, then I recommend you find a way to blackmail someone with Amazon. Perhaps you could threaten to downgrade their shipping from next day to standard.