Be sure to consider the dark background and choose light-colored flowers and accessories. The fall issue of Accent on Style, a decorating magazine produced by Hancock Fabrics, shows how to use fabrics to disguise an unused fireplace. The end product resembles a quilt on a quilt stand. A second idea is to make a stretched curtain of fabric with a rod pocket at the top and bottom. You'll need a length of fabric about twice the width of the opening.
Tension rods hold the gathered fabric in place between the walls of the firebox.
To add a little more romance, and for something a lot easier to find, look for decorative candle holders. These can be free standing or attached to a mesh screen. Burning candles look great either in a fireplace you never use or in front of a neatly stacked pile of wood. Candelabrum specially made to warm up the look of a fireplace are easy to find. Service Merchandise carries several styles.