Module: workflow_fields

The workflow_fields module extends John VanDyk's workflow module by allowing CCK node fields to be made invisible or read-only depending on the current workflow state. The workflow state form is extended to show all node fields with appropriate controls to hide and/or disable each field for that particular state.

This functionality is useful when a workflow moves among users who have different permissions regarding the document flowing through them. Which is the case in most every workflow we've encountered.

Check it out: http://drupal.org/project/workflow_fields