Do you still remember this? It was a good post about the OS X install via the network using a GNU/Linux install server. I went back to read and use it after a few days to install the version 10.5 (leopard) of OS X and it worked well but there's a couple of things missing in that post which I'd like to share here.
The problems were mainly in mounting the leopard disc. If you try to do that on a GNU/Linux system you should only see some files about bootcamp, it is indeed a double format dvd which includes two sections, one is iso9660 formatted and another is hfs+ formatted. To find the files I mentioned, you'll have to mount the hfs+ formatted section ... which is hidden but you can find it using this very helpful link: Mounting HFS+ Hybrid Disks on Linux.
Also, because of the additional steps, when you're at this:
dd if=/dev/hdc of=/tftpboot/macosx.img
you'll have to replace /dev/hdc with the /dev/loop0 device created by the instructions linked before.