Microsoft Knowledge Base Article 927070 contains the following INTRODUCTION:

The Active Directory service uses Domain Name System (DNS) for name resolution. However, in a Microsoft Windows 2000-based forest or in a Microsoft Windows Server 2003-based forest, programs that depend on the NetBIOS namespace may require Windows Internet Name Service (WINS).

WINS provides a dynamic replicated database service that can register and resolve NetBIOS names to IP addresses that are used on a network. WINS is required for applications that call the NetServerEnum function. This function depends on NetBIOS. Programs that call the NetServerEnum function include Cluster Administrator, SQL Administrator, SNA Server, and more. Additionally, WINS is required to populate Network Neighborhood on every computer.

In a forest that contains more than one domain, you must use unique NetBIOS names for all the computers in the forest, regardless of the domain to which the computer belongs. This is true because NetBIOS name resolution will be required between the domains.