Pokémon FireRed Version (ポケットモンスターファイアレッド Pocket Monsters Firered) and Pokémon LeafGreen Version (ポケットモンスターリーフグリーン Pocket Monsters Leafgreen) are remakes of the Red and Blue games. These games, like the original, take place in the Kanto region and also includes the Sevii Islands which were not in the original. Though these games are remakes of the Generation I games they are considered to be Generation III games, now with better graphics and many new features.
Let me tell you about Pokemon FireRed and LeafGreen. These games were great. People say they're not as good as the originals, but, meh, when is that the case with anything? The graphics were way better, let me tell you. Not as colorful as Ruby and Sapphire, but they were ok.
Now that I think about it, there's not a whole lot to say about FireRed and LeafGreen. They didn't change much. I think their main purpose was to basically be an apology for not letting you transfer Pokemon from Gold and Silver. Yeah, they weren't particularly innovative, but their good games. If you haven't played them, it's no big deal if you don't, but they're worth a shot.