Here's a list of free resources to help you learn how to better pose people for portrait photography.

1. The Zeltsman Approach to Traditional Classic Portraiture
   Sixteen chapters containing lots of detailed information on evaluating the face, posing men and women, groups, children, and much more. Each chapter contains many photographs demonstrating the posing techniques being described.
   This is a great resource, but it'll take you a while to read through the entire guide!
   
   
2. The 1-2-3 Posing Technique
   This is just one section of the comprehensive Benji's Studio Lighting and Posing Tutorial, and looks at the 1-2-3 posing technique for females.
   
   
3. The Portrait Photographer
   This blog contains many valuable posts on many different aspects of posing for portraits, and is worth browsing through.
   
   
4. Portrait Photography Tips
   A list of 22 posts from Digital Photography School on portrait photography, including a number of articles on posing.
   
   
5. Portrait Photography's Power Posing Part I: The Components
   This post looks at the various components that need to be considered when posing people, including the hands, feet, arms, head and chin, etc, with some comments on how techniques that can be used for each component to achieve different results.
   
   
6. Portrait Photography's Power Posing - Part II: The Poses
   A follow-up post to the one listed above, this time looking at a few different poses.
   
   
7. Simple Posing Tips for Better People Pictures
   This page provides a list of recommendations about posing a subject to provide natural-looking poses.
   
   
8. Posing the Question
   A brief look at the impact of body language on portraits, and how it should be used to ensure the pose portrays the correct context.
   
   
9. Portrait Photography - Posing the Subject
   A useful list of suggestions on posing a subject's shoulders, head, eyes, hands and more.
   
   
10. Posing Samples
    An 18 page PDF containing hundreds of sample poses for an individual female, individual male, and a couple.

And finally, just a quick plug for Digital Photography School's The Essential Guide to Portrait Photography eBook. While it's not a free resource like the others listed above, this USD$19.95 eBook is a collection of great tutorials and articles looking at many different aspects of portrait photography, and includes many articles on posing.

Are there any other free resources on posing people for photography that I've missed?