I had help from the co-developer. I designed the world map in RPGmaker 2000 and took a screen shot of it. Then used photoshop to give it a "map" like vibe.
Try desaturating the continents, adding in a yellowish brown tinge, and using layer blend modes. The way it currently looks, it seems like it was just a parchment texture with an opacity drop to reveal the world map layer below.