cdrecord -v -pad -tao -eject speed=8 dev=/dev/hdc sarge-i386-netinst.iso
BTW:
The image came from here: http://www.debian.org/devel/debian-installer/
Or even just:
cdrecord dev=/dev/cdrom sarge-i386-netinst.iso
And this time I went for:
http://cdimage.debian.org/pub/cdimage-testing/daily/i386/
which fixed some problems I was having with the 2.6 kernel not wanting to mount the root image on my old 233MHz machine... (turning off things in the BIOS and managing to boot Knoppix under 2.6 let me know it was possible)