I am gonna continue to have faith that a real SDK will come out of Apple, perhaps during Leopard, or iPhone v1.1 or something. Apple isn't 100% behind the Web2.0 stuff (because there's no interface guideline or template from them, so we have all this garbage out there) and released it so we'd have SOMETHING to do while they figure out how to keep iPhone from crashing even with their own apps. And, as a previous poster said, you have to be on the net to use most of them (or, that data:// trick from an earlier blog post here).
With an actual SDK, we could replace that horrible "iPod" with something resembling the actual iPod. We could access the wifi and do a iStumbler app. We could write a better Mail client, because iPhone v1.0's Mail sucks balls. The Phone app is pretty perfect, though.
I just think Apple put all their code monkeys on making iPhone v1.0 usable and stable(ish), and even then it's mildly buggy. It's not only possible, but likely, that the APIs they're using to control the phone aren't all the way developed yet, and there probably isn't any set of common libraries (based on the fact that Notes, Weather, and Bookmarks are all completely different manifestations of a "list", implying there isn't a NSTableView yet. Perhaps they're all working towards a SDK for us as we complain.