Bring or send a disc of the songs that you would like to include on your DVD presentation, or if you don't have a disc, just make a list. I can help you with your choice if needed. It is important to consider the mood that you would like to create. Try to choose music that has special meaning for the people involved. You need approximately 1 song for each 20 photos (and perhaps 1 extra song).
DVD Features Getting Started DVD Compatibility Sample Clips