Warning: You are viewing old, legacy content. Kept for posterity. Information is out of date. Code samples probably don't work. My opinions have probably changed. Browse at your own risk.
Nov 17, 2008
I posted about this in relation to Drupal 5 here. Now it's time to do this with Drupal 6...
Let's recap: Node reference field allows you to add a link from one content item to another. You add the reference to another existing node when you create a node with a nodereference field. The node being referenced must exist in order for this to work.
This bit of code lets you reference a non-existent node. The referenced node is created when the validation fails to find an existing node.
Some very basic code is attached. To try this, put the two files in a folder in your site modules folder. (see attached files). This code has been tested with Drupal 6 and CCK 2.
Update: The download was removed from this page as someone else took the code I provided and create a Drupal.org project for it.