Share Sniffer
http://www.sharesniffer.com/
Share Sniffer is a program that searches for Microsoft Windows machines on the internet that have opened their shares to all users without a password.

Direct Connect
http://www.neo-modus.com/
Direct Connect allows users to share multiple directories from their local and mapped disks with other users over a TCP/IP network. All users' shared files are available to all other users; no passwords or hassles are required.