Tracking Shares on NT4 Network

We have had an outbreak at work recently where Win9X workstations have had folders/drives shared out and apparently read by non-owners/unauthorized persons. The workstation owners have claimed that they did not create the shares on their workstations. Sounds very nefarious!

It would be handy to be able to compile a list of workstation shares and, more importantly, keep track of when (and who)used the shares.

Any ideas on the best way to monitor/manage this type of network activity?