As part of a bonus for Final Fantasy Explorers, Japanese players can check out the first Final Fantasy in stereoscopic 3D.
http://www.nintendoworldreport.com/news/38537/original-final-fantasy-coming-to-3ds-eshop-in-3d-enhanced-release
The original Final Fantasy game is coming to 3DS in an enhanced form alongside the December release of Final Fantasy Explorers in Japan.
Retail copies of Explorers will include a download code for this retro bonus, which will be sold on the eShop a month after the release. The version of Final Fantasy seems to resemble the recent PSP remake, with cleaner-looking graphics. The 3DS version will also display in 3D, likely in a similar way as Nintendo's own 3D Classics.
Additionally, a prologue demo is set to come out in Japan before Explorer's release. This demo supports multiplayer and online play.
Final Fantasy Explorers, which could likely best be summed up as a Final Fantasy take on Monster Hunter, is set to come out on December 18 in Japan. No word yet on a worldwide release.