The Netbios Share Samba Scanner can scan C classes and reveal all open shares. It will tell you all the information and even show the content of the shares. It will also show you shares that are not accessible. You can provide a username and password to it.
Netdiscover is a network address discovering tool
that was developed mainly for those wireless
networks without DHCP servers, though it also
works on wired networks. It sends ARP requests and
sniffs for replies.