Final Fantasy IV debuted on the Nintendo Entertainment System in 1991, which means that if it was a human being it likely would have graduated college by now. But it's not a person, it's a videogame, and so instead of going to college, it's gone to Steam.
The Steam release of Final Fantasy IV is apparently a remake of the much-more-recent Nintendo DS edition of the game, which came out in North America in 2008. It's been "optimized" for the PC with support for controllers, Steam achievements and an "all-new system for charting dungeons and uncovering the secrets within."
Beyond that, it's hard to say what exactly is in store. The game literally just appeared on Steam without warning, and as far as I can tell neither Valve nor Square Enix have said a word about it. This may be the stealthiest game launch I've ever run into.
Odd though it may be, Final Fantasy IV is in fact live now on Steam and will set you back $16. And there may well be more to come; Final Fantasy III launched on Steam earlier this year and in February, Producer Yoshinori Kitase said the advent of Steam has made the PC a much more attractive proposition, and that Square Enix is now " very interested " in bringing more Final Fantasy games to the platform.