I personally use DVD X Copy for copying DVD's, and it works great. You basically pop the DVD in, the program temporarily saves the file, then you pop in a blank DVD, and it compresses and burns the files, including menus, bonus features, etc.
dvd has .vob (mpeg2 files), .ifo (the file that control the vob files) and .bup (ifo backups files). you need a software dvd decoder (power dvd, Windvd) to play them. real one and window media player will borrow that codec of that software to read the dvds after you install them