Need a tool for finding open shares

I am looking for a tools that I can use to scan Windows machines in an active directory domain and look for open shares.  I'm looking for the tool to do the following:

1. Scan at either the domain level, or a range of IPs
2. Enumerate the shares available on the machine
3. Identify the defined access on the shares for the machine.  (Report all the defined access on the share, not just a single user or group that I have to define during the scan.)
4. NTFS permissions defined on the filesystem accessible by the share.

A free tool would be preferred, but we are having problems locating a good tool that will do a wide scan (free or not).

If not a single tool, is there a combination of tools to accomplish what I need?

Any suggestions?

Thanks!