Document network Shares and Permissions

I am a new Network Administrator for a company with an enterprise-wide network, with about 40 Windows 2000 servers, and a few NT 4 thrown in (Including PDC and BDC). I would like to get suggestions for any software tools, free, expensive, it doesn't matter. What I need is something that will facilitate creating documents for an upcoming Srbanes-Oxley Audit. Specifically what I need to dois create Excel spreadsheets of all of the available network shares and permssions. We are currently on an NT 4.0 domain (I know! we're upgrading to 2003 - also why I need tools!) Any suggestions?