I have a Windows Server 2003 server that I need to have at least .NET 2.x installed on.
Is there somewhere within the OS where I can tell it to download it from Microsoft?
or
Do I have to download the runtime from Microsoft manually and then install it?
(I know I can do it this way, but is there another way?)
You can get the .NET Framework 2.0 Redistributable and .NET Framework 3.5 Redistributable from Microsoft downloads and run them manually on the server. If you have more than one server, you should have them setup to recieve updates from a central area much like Zypher said.
Hope this helps some.
You can either push it via WSUS, or you are going to need to download it from MS (preferable to a central software share so you only have to download once) and push it via GPO/SCCM/some other install solution. or manually install it.
You can use Web Platform Installer from Microsoft. That's easy and very efficient.
Run Windows Update and Select the features you want to install.