All depends on the file extension you are sending the music as.... the person receiving needs to have a player that can open and play that particular file extension.......
VLC Player from Videolan.org, for both windows and a version for Mac, is a super player which can handle just about any format you send its way....
http://www.videolan.org/... So it would work for you with the Mac version and the receiver of your file candownload the PC Windows version or the Mac version depending on what computer they use.......
Click on the site link that I provided and you can read all about the player and also get the FREE download of the programs........ Uses a lot less resources than Microsoft Windows Media Player and handles a heck of a lot more file types......... Yuo can do a Google search for other players, but this is the preferred player from several tech sites I utilize or participate with.......
I should also add that this program is suitable for Windows 7 Operating Systems as well. Just be sure that the user downloads the correct player for their version of operating system and computer type (PC or Mac)..........
Have fun and Happy Puterin'..... BT