HOW TO: Hide music in your pictures
This page lets you hide small samples of MP3s in GIF files. The GIF format allows for an 
"application extension block" - an arbitrary section for applications that isn’t checked by the GIF parser. Meanwhile, Winamp and other MP3 players ignore all data in the file that isn’t marked as an MP3 block. The result: the picture viewer ignores the music, and the MP3 player ignores the picture. MP3Gif: hide music in your pictures.