The New York Times reports on Lytro “Shoot Now, Focus Later.” The Lytro camera coming later this year uses a micro lens array to capture images without having to set focus. You can change focus interactively while viewing.
Further reading, forwarded by Howard Preston: http://graphics.stanford.edu/papers/lfcamera/
and the technical paper: http://graphics.stanford.edu/papers/lfcamera/lfcamera-150dpi.pdf.