To get CD and DVD burning running under debian unstable on a 2.6.x kernel
Under 2.6 ide-scsi (SCSI emulation) is deprecated. It's recommended to use ide-cd instead. Using ide-cd under debian will also correctly set up sysfs details to help you get udev to auto-create the correct devices.
So - first make sure you're using ide-cd. This means - make sure you remove ide-scsi from lilo.conf (not sure about grub), and then check /etc/modules. It should contain the line ide-cd and not ide-scsi.
Secondly, the udev packages have done the work required to get udev to recognise the devices.
udev processes the rules files in /etc/udev/rules.d in alphanumeric order. If you use the non-devfs naming style (which I prefer) the file /etc/udev/udev.rules is symlinked into /etc/udev/rules.d.