Either (safest) make sure the music is embedded or put the music in a folder
with the presentation, insert and send the whole folder. The recipient will
need to put the complete folder on their hard drive.
Embed Sounds:
Wav Files
Either change the setting in Tools>Options>General - "Link sound files with
size greater than" to 50000 THEN insert the sounds
-- OR
Insert as a transition sound (Transition pane > sound drop down scroll down
to other sound
MP3 files
Download the free program CDex and with it adda wav header
(CONVERT > add a riff wav header to mp2/3)
This will make powerpoint believe that it is a wav file and can be inserted
as above.