One billion Chinese means two billion screens.
Nintendo has been selling their products in China for awhile now, through the iQue company. The line started with a modified N64 controller that played downloadable games on flash cards. The line has expanded and now the GBA and GBA SP are available in China as well.
The iQue web site was recently updated, and now shows a Nintendo DS and a countdown. The countdown will end on June 15. More information will probably be revealed on this date.