This project includes:

• a force-directed layout algorithm in C#. See Wikipedia page on force-based algorithms
• a Silverlight control (SilverSpringCanvas) that uses the algorithm to layout child elements

• The springy.js javascript library by (@dhotson) provided some inspiration for SilverSpring, particularly the idea of visualizing the graph during the layout calculation.
• The contents of a stackoverflow post helped to work out the required arrow drawing code. See stackoverflow post.

See an example here