When you are creating a presentation sometimes you would like to add a sound or music file. There are a number of places to download sound files that are not only free but royalty free as well.
Soungle is full of awesome sound effects
Partners In Rhyme Royalty free songs and sound effects
Cool Midi Free Midi file downloads
Midi DataBase has links to free music downloads
These sites should have any sound file you are looking for. I use this as an opportunity to discuss copyright infringement and to piracy.
Hope this helps