I found this information comparing Dutch Process cocoa and natural cocoa at David Lebovitz site tonight, thought I would post it here since questions about this arise from time to time.
http://www.davidlebovitz.com/archives/2010/02/cocoa_powder_faq_dutch-process_v.htmlNatural cocoa on the left, Dutch-process on the right

Contents:
What's the difference between Dutch-process and natural cocoa powder?
Can I use Dutch-process and natural cocoa powder interchangeably in recipes?
How is cocoa powder made?
What does it mean to 'bloom' cocoa powder?
Can I substitute ground chocolate for cocoa powder?
Can I use sweetened cocoa powder in recipes that call for cocoa powder?
Why do some recipes say to sift drying ingredients with cocoa powder in them, and others say to whisk?
How do you store cocoa powder, and how long does it last?
Can I dust a cake pan with cocoa powder instead of flour?
Plus resources links for recipes, products and more information
Enjoy!