Bah, I wish I could provide you with some dedicated FF5 sites, but none are available. These multi-game sites will have to do.

Cave of Narshe

They cover all the Final Fantasy's. In their FF5 section they have character info, magic/weapon/item lists, etc. all the stuff you'd expect a walkthrough to have. They also have some maps, art galleries, screen shots, fan art, fan fics, and more.

IcyBrian.com

A haven for the RPG enthusiast. His FF5 section offers all sorts of goodies like fan art, fan fics, and more!

Final Fantasy Shrine

One of those sites that cover all the Final Fantasy's with info and various media.

Final Fantasy Extreme

Same as above.

Eyes on Final Fantasy

Same as above.

Final Fantasy Online

Same as above.

Final Fantasy Addicts

Same as above.