Are you talking about downloaded movies that your wifes pal has stored on her hard drive that she would now like to put onto disc to put into a dvd player?
If so, all you need is some dvd burning software and some blank discs. Most laptops come with some DVD burning software already installed, but if she does not have this software she will need to buy/downoad one. Nero is very popular and I have used this many times in the past.
Does you friends DVD player have a USB port? If so she can forget about the discs and simply transfer the movies to a USB drive and plug it into her DVD player.