Hello,
The AVI tools that are provided with Vision allow for data to be added to your video. Sound information can be stored this way, but if you are looking for a way to add audio support to your video (such that it will play the sound file when the video is played in Windows Media Player or other applications) you may want to look into finding a shareware or freeware product that can accomplish this. LabVIEW does not have tools specifically targetted to this operation.
Good luck,
Robert