I swear I saw a copy of the official guide for the PSP remake for sale at Gamestop, but I'm not sure you'd be able to find it there easily anymore.

As others have suggested, walkthroughs are generally more detailed and in most ways better than commercial release player's guides; the only thing you're going to lack is pretty pictures, which you can probably do just fine without.

Edit: here's the FFT: War of the Lions guide on Gamestop.