How to hide files in JPG's

Fascinating tutorial on a technique to emdeb files in jpgs. Look at '[ebook] raymond chandler - the big sleep.jpg' in K:\Design A-J\Digital. This is a jpg of the cover of the book, but embedded is the e-book. Cool idea to hide ‘easter eggs’ in images. Also very much like the style of the tutorial, maybe we could use this to show how to use delicious? How to hide files in JPG's