A computer developed for poor children around the world, dubbed "the $100 laptop," has reached a milestone: Its price tag is now $200. The One Laptop per Child Foundation, founded by MIT Professor Nicholas Negroponte, has started offering the lime-green-and-white machines in lots of 10,000 for $200 apiece on its Web site (http://laptopfoundation.org/participate/givemany.shtml).