Corresponding node references is a module I contributed to drupal.

What does it do:
It syncs the node reference between two node types which have a nodereference to each other, so double editing nodes is no more needed. If one node has a reference the other node receives also a reference to the saved node if it is referenced in that node.

Project page:
http://drupal.org/project/cnr [2]

Drupal account:
domidc [3]