This webpage provides an abridged and to the point overview of the process. In fact upon second look it seems there is a ton of useful information at this site.
The Real Cider and Perry Page
Cider: Making, Using & Enjoying Sweet & Hard Cider, Third Edition (Amazon referral link)
I keep coming back to this book to figure out my barrel issues and understand the process of making hard apple cider. While I think I generally understand the process it helps to have a dead tree version to revisit and provide context.
CvilleKevin's extensive experiments with juice, sugar and yeast documented on the Homebrewtalk forum...