They are two different animals. The postage stamp is made of a gazillion small squares and the log cabin is strips around a center square.
I recently finised a Steps to the alter which is similar to the postage stamp. They are alot of fun and eat up all your scraps but time consuming, all those little pieces.
EDIT: Great tutorial Peckish. That's how I did mine along with piecing individuals squares to use them up. The using them up part didn't work! :-D