You can try email, but some email servers put a file size limit on attachments. If he has an FTP server set up on his end, you could FTP it over. Worst case, put it on a USB (thumb) drive and mail it to him.
You can also try compressing them using WinRaR or some other Zip type program. Audio can be rather large if in WAV or other formats (loss less). MP3 are relatively small but still might exceed your mail sizes. As a last resort you could burn them to a cd and mail the cd. Please be sure the files you are duplicating are not copy righted or otherwise the legitimate property of someone else. These forums do not encourage any forms of piracy.