First, you need to create a boot CD. Download
and burn it to make a bootable CD (the file is only 114M). You can verify the ISO file with the SHA1SUM file in the same directory.
I've never done a network install using a local server, but here's an article from 2004 (see the section "Installing Using a Network").
The file above may also be named "boot.iso" which is the name used in the article. If instead you decide to download packages from a remote server, the path you would use would look like
(if possible replace with a nearby server). It should have a subdirectory called "images" which in turn contains stage2.img and boot.iso (which is identical to the ISO file above, just with a different name). You need to write this path down in advance so you can enter it when prompted.