"For programmers, this is a huge challenge: What you write for the office PC has to work on the phone, and what you were writing for the phone has to be accessible and smart-looking on a much larger screen. Are you ready?"

Assuming you're talking about web applications here, then the answer is yes, we're ready. Modern web developers and designers should be using Plain Old Semantic HTML (POSH). One can then stylizing that content using unobtrusive CSS and add behavior using unobtrusive JavaScript. One of the benefits of using pure CSS design is that you can have different style sheets for different media. In the context of this article the two media types would be "screen" and "mobile."