ShareScan actually looks for Windows file sharing (SMB) shares on the network.
There's
phynd which indexes all available network shares on the network and is designed to run as a search engine, but it isn't all the easy to setup.
You could also do something like
nmap the network looking for shares on port 139.
Note that the sort of scanning the ShareScan and these programs do can cause the network administrator to get very annoyed as it creates a lot of excessive bandwidth on the network. I've seen some places where SMB sharing has been blocked due to the bandwidth these programs use.
- proton