The NetBom tool from CadEnhance concisely documents the differences between revisions of Net Lists and Bills Of Materials (BOMs) of a PCB board design.
It also produces Human Readable BOMs and helpful hyperlinked NetLists
NetLists From Many of the Major EDA Designer Tool are supported:
NetBom Now supports Orcad Capture DSN files directly so the User can produce NetLists/BOMs and see the differences between 2 DSN files.