One of my personal biggest inspirations, Edward Tufte, the king of information design and one of those old farts who apparently just can't grasp why they'd want to use RSS, has a review up on his website about the iPhone's interface. He also references some of his earlier work that reinforces his opinions.

The verdict is, he mostly likes it a lot, although he criticizes the weather and stock apps for mis-utilizing the high-res screen by showing too little information. I can dig it.

The main points seems to be:

1. eliminating "computer admin debris" from the interface, letting users directly manipulate the content, has allowed the tiny screen to contain the maximum amount of data possible.
   
2. Changing the paradigm from "temporal stacking," which becomes instantly tough to manage and navigate on a small screen (enter Exhibit A, Windows Mobile) to a sideways navigation on the same "surface" helps users keep track of "where they are."
   

My favorite takeaway, though, is something that is central to much of Tufte's work.

"Clutter and overload are not attributes of information; they are failures of design."

I love that quote. It's a principle Apple occasionally struggles with: they'll rip out functionality you might wish you had, in the name of simplicity. That being said, though, they do get it right much of the time, and the iPhone proves that.