SharePoint Portal Server 2003 Service Pack 2 was released today.  Download here

SP2 introduces support for the following: 

·         Support for running on 64-bit machines in 32-bit emulation mode

·         Support for Reverse Proxy and Alternate URL support

·         Support for IP-Bound virtual servers

·         Support for off-box SSL termination

·         Support for SQL Server 2005

Lastly, SharePoint Portal Server 2003 with SP2 will be Kerberos-enabled by default.