CloneDVD to make it easy, if 8.5Gb to 8.5Gb (Double Layer discs)
DVD Rebuilder if you need to shrink it from 8.5Gb to 4.7Gb (Double Layer disc to Single Layer disc)
Nero or any other burning software if it's 4.7 Gb to 4.7Gb.
*4.7Gb movies are always ripped movies, no copy protection, which means you can copy them without any extra hassle.