Final Fantasy 3 is the only game in the series that had never been given a western release until now, but if you've ever played any versions of the old 2-D Final Fantasies, you will have a pretty good idea what to expect - lots of random battles, exploration, bosses and dungeon crawling. Although the underlying template of the old game is still in place, all of the graphics have been given a complete 3-D overhaul, making this one of the prettiest games to appear on the DS so far.
FF3's twist is the job system, which I can vaguely remember was also used in FF5. Each of the four characters starts as a freelancer (a generalist), but you can assign them to particular specialties, changing their abilities, appearance and the way they level up. This leads to some interesting choices in how best to customize your party, since characters learning multiple jobs will level up more slowly than those who specialize in a single class.
The plot is fairly unfocussed and generic compared with later instalments, though the characters have been given names and more personality than in the original version. In an interesting twist, the world you start in is not the world in which the majority of the story takes place.
You can control the game entirely with the stylus, but it's frankly a lot easier to put it away and use the face buttons. It also fails to make full use of the upper screen. This is definitely an old-school game. The difficulty curve is pretty steep, and there's at least one spot where you're unlikely to progress unless you've read the manual. But it's very playable in short bursts, and one of the best DS-specific RPGs to date (although a similar DS remake of the more epic Final Fantasy 4 is now in the works).