GO!NotifyLink Enterprise Server:

Network Load Balancing with GO!NLES

1. Install Windows 2003 Enterprise server.
   1. During install of the network components, select Network Load Balancing to install it.
2. Open the Network Load Balancing Manager under admin tools.
3. Right click Network Load Balancing Clusters and select New Cluster.
4. Enter the IP, subnet and FQDN of the cluster and select unicast.
5. At the connect window, enter the IP address of the first machine in the cluster and hit connect.  Select it and then hit next.
6. Once the cluster is created, right click the cluster and select Add New Host to add another machine to the cluster.
7. Installed NLES on each machine in the cluster.
8. Disable Internet Message Service on all but one of the cluster machines.

You may also reference these links from Microsoft:

      http://support.microsoft.com/kb/323437 

      http://technet2.microsoft.com/windowsserver/en/library/65319bac-2efe-4764-8752-d091447dddbe1033.mspx?mfr=true