Yesterday John Gruber wrote about the upped pixel density in the upcoming iPhone (960x640 instead of 480x320), and why Apple did this. He also wondered what the consequences for web developers would be.
Now I happen to be deeply engaged in cross-browser research of widths and heights on mobile phones, and can state with reasonable certainty that in 99% of the cases these changes will not impact web developers at all.
The remaining 1% could be much more tricky, but I expect Apple to cater to this problem by inserting an intermediate layer of pixels. (Later John pointed out that such a layer already exists on Android.)
One caveat before we start: because they’re unimportant to web developers I have mostly ignored the formal screen sizes, and I’m not really into disucssing the ins and outs of displays, pixel densities, and other complicated concepts. So I might use the wrong terminology here, for which I apologise in advance.