You want the file darwinx86-801.iso
- Set machine type to Windows NT 4 (you want to avoid an EFI machine)
- PIIX3 chipset, 256MB of RAM is okay. Set ethernet controller to Intel 82540EM (Darwin 8.x has a driver for it)
- Enable ACPI with
VBoxManage modifyvm OpenDarwin --acpi on
- Set up storage: PIIX3 controller with host i/o cache enabled.
- Virtual hard disk should be first disk. I created an 80GB drive.