Amazon's Kindle device brought low-power reading in bright light to the masses. On the downside, the Kindle is a single-purpose device and has a very slow screen refresh rate, far too slow for PC applications.
Pixel Qi is an offshoot from M.I.T.'s OLPC one-laptop-per-child project. Pixle Qi was founded by Mary Lou Jepsen, former Chief Technology Officer for the OLPC project.
OLPC was never as successful as anticipated but it did, ironically, start the netbook revolution of low cost, low-power notebooks.
A dual-mode LCD screen would behave like a normal backlit color screen for the usual notebooks operations. At the flip of a hardware (or software) switch, however, the screen turns into a lower-power monochrome screen capable of being viewed even in bright sunlight just like a book. Unlike the Amazon Kindle, screen refresh is just as fast as in normal backlit mode.
Dual-mode production LCDs will probably first be seen for netbooks, where portability and low-power uage are most important.
I'm a Frisbeetarian - we believe that after we die our soul goes up on the roof & gets stuck. <- My terminally ignorant thread-trashing cyberstalker: JustMeOw (aka "the whiner")