I mean as if having Red,Green, Blue, Yellow, Gold, Silver, Crystal, Ruby and Sapphire wasn't enough for Nintendo.
They are now re-releasing Red and Green in Japan with slight tweaks with the titles Fire Red and Leaf Green. Other than some tweaks, and being compabitle with Ruby and Sapphire, I don't think there is much new.
Boy o boy, now you got to re-buy 2 old games in order to get all the PokeMon in 2 new games....
http://pocket.ign.com/articles/437/437883p1.html