Something that I think might help would be to look for high-res scans of old book and parchment pages on-line. Look for university conservatory sites that specialize in preservation. If there are no copyright issues I would clone or paint out any text that might still be there (The less cloning the better) and work over top of the page. Your edges will look more naturalistic and the texture will have it's own unique flavor.
Another trick is to make a pit stop at your local used/antique bookstore. I've found some awesome textures prowling the French poetry sections. Part of the fun is just poking around and seeing what you can find.
kind of like the background for my other map?
Map of Serth
thats what i wanted to use, but the freind didnt want that, he liked what i made. A shame, because the other papers look for professional, and just plain better