$180 Portable Solar Power for Your Laptop, MP3 Player
Pat from Will Blog For Experience writes about his experience using a home-made, portable solar kit to power his MacBook. He says: "This kit weighs about 2 lbs, costs $180, and will power my Macbook for 1.75 hours (1.83ghz, browsing the web and checking email via Airport Extreme, bluetooth off, screen brightness about 70%) with a little more than 5 hours of good sun." The folding solar panel he uses is available from the Alt Energy Store. See a picture of the entire kit after the link.