Look at this ad I saw on another website. They have a cream that keeps your heels from cracking (or breaking I think) even in the driest weather. I think that is amazing. I didn't even know heels crack more easy when they are dry. I wish I had this the last time I broke one of my heels.
http://www.shoes.com/productimages/shoes_im07027.jpg
It is called Dr.Scholl's. Cracked Heel Relief Cream
Product Description: Prevents heels from cracking even during the dry seasons.