Audit of MS licenses

I have recently taken over a network that is an absolute mess. One of
my first tasks is figuring out just how out of compliance we are with
our Microsoft licenses. The majority of the company still has a need
for Access 97 (if you can believe that), but that need is going away in
the coming months. I am going to upgrade Office throughout the
company, so I would like to know where I'm at first. There is bound to
be a Microsoft or freeware tool that makes this job a snap, right??