Nice writeup on the process used to design an iPad app. Applies to websites as well. Be sure to check out the link in the second comment on a similar writeup for the desktop version of the app.
Information on designing for screens with high pixel densities (such as the new iPad and iPhone 4/4S). These screens have double the resolution of the previous versions.
A nice article on the process used by Patrick Welker to redesign the icon for a popular RSS app on iPad, Mr. Reader. Shows how the first solution isn't always the best.