What's WINS?

Windows Internet Name Service (WINS) is Microsoft's implementation of NetBIOS Name Service (NBNS), a name server and service for NetBIOS computer names.
Effectively WINS is to NetBIOS names what DNS is to domain names — a central mapping of host names to network addresses.
Like DNS it is broken into two parts, a Server Service (that manages the encoded Jet Database, server to server replication, service requests, and conflicts) and a TCP/IP Client component which manages the client's registration and renewal of names, and takes care of queries.
http://en.wikipedia.org/wiki/Windows_Internet_Name_Service



WINS was designed specifically to support NetBIOS over TCP/IP (NetBT).
WINS is required for any environment in which users access resources that have NetBIOS names.
If you do not use WINS in such a network, you cannot connect to a remote network resource by using its NetBIOS name unless you use Lmhosts files, and you might be unable to establish file and print sharing connections.


WINS and DNS are both name resolution services for TCP/IP networks.
While WINS resolves names in the NetBIOS namespace, DNS resolves names in the DNS domain namespace.
WINS primarily supports clients that run older versions of Windows and applications that use NetBIOS
Environments that include some computers that use NetBIOS names and other computers that use domain names must include both WINS servers and DNS servers


http://technet.microsoft.com/library/cc784180.aspx