You are seeking guidance on how exactly to go about configuring your environment so you can use an IIS 6.0 server to host content at Distribution Centers (distribution points) for an LUA 2.x infrastructure.
One LiveUpdate Administrator 2.x server is usually all that is required, even in large environments. A well-resourced LUA 2.x server can successfully distribute contents in up to one hundred Distribution Centers (DCs) throughout the corporate network. Endpoints and other Symantec products can then download their necessary updates from these convenient DCs.
Please download the attached pdf document, which remains accurate for LUA 2.2 and LUA 2.3:
Managing Distribution Points with LiveUpdate Administrator 2.1
The version of IIS supplied with Windows 2003 is IIS 6.0.