SharePoint Extranet
It has been out some time (since January 6th), but I know some of my clients are waiting for it. :-)
Overview
This document explains how to deploy SharePoint Portal
Server 2003 across an extranet. The white paper discusses
how to configure a SharePoint Portal Server deployment so
that users outside an external corporate firewall/proxy
server can access information on a portal site that is
inside an external corporate firewall/proxy server. It
specifically discusses using Microsoft Internet Security
and Acceleration (ISA) Server 2000 and ISA Server 2004 in
what is generally considered to be a reverse proxy
configuration.