I only skimmed through it, but I didn't see too much that was
groundbreaking. At the very least, if you're an iPhone web designer, it will
probably save you many hours of trial and error.
Let me recommend, though, that you skip to this section:
iPhone HIG > Metrics, Layout Guidelines, and Tips > Be Aware of Default
You'll find a page that describes a "multiple select element". It looks like
a drop-down list, except I guess you can select more than one option. I
haven't used an iPhone long enough to encounter one of these in the wild,
but it seems pretty cool. In some cases, it could save a ton of space by
replacing a long list of checkboxes. Can anyone who has used this widget
before comment on its usefulness?