Deep Thought, the man who brought us the Icarus import script, has written a great introduction to compositing in Blender using the greatly anticipated nodes system.
Compositing with nodes is slated for the next release of Blender and already the latest test builds* are allowing us to start understanding and using nodes to great effect. If you would like to get in on nodes early, Deep Thought’s intro to compositing with nodes (pdf) is a must see.
*Keep in mind that the latest builds are not the final release and should be used for production with caution.
