I use Nero vision. I open it and then go to make dvd video. This opens a window to import files. Import the file you want and follow the next button to create menus etc finally getting to the button to burn dvd. Nero will the convert to the correct format and then burn to dvd.
I've used this probably a hundred times for avi files ( I download a lot of films which usually come as avi files) and also for files from my camcorder. the dvds created in this way even play on my old dvd player which won't even accept recorded cds. It works well.