File list spreadsheet
Sounds like you need a DAM solution. We use Fotoware but you need the server version if you are working with lots of assets and you need a multi-user environment. There are plenty of single-user, desktop DAM solutions but very few multi-user, network DAM options.
Well I'm working in a digital advertising office and the other members of the team can track final project files we've created and link them to other files we're working with etc... don't' know if that really makes sense?