x2 This man knows of what he speaks.
I redid mine in my van. It isn't like it is FUN, but once you have done it once, you realize there really isn't anything to it. Just make sure that your backing is clean, spray your adhesive on both your headliner and your headliner backing, allow to tack up, then lay it down flat and keep any wrinkles or bubbles out.
Look for a local fabric store. Most really large / commercial fabric stores have headliner in all kinds of colors as well as other material that you may rather have instead. They usually carry the adhesive you need too.
Here is my headliner replacement if that helps you any:
http://www.stevemeadedesigns.com/board/ind...astro+headliner