Creating Prints of Large Fractals?

jkoshy asks: "I would like to make very large (10'x10') color fractal images using A4 size printouts that I would be assembling to make up the final picture. Most fractal generation programs that I have seen are designed for on-screen fractal viewing. Are there any programs (or scripts driving fractal generation programs) that can generate large printouts of fractal images?" I can't resist a good fractal poster and would love to be able to produce one on my own, as well. In addition to the poster's question, how difficult is it to get posters made from fractal images? What resolutions are typically required?