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.