the comand
Code:
dmesg|grep *
(where * is replaced with sd, scsi or sg) might answer your question.

here is what it looks like for me.
dmesg|grep scsi
i2o_scsi.c: Version 0.1.2
scsi0 : SCSI emulation for USB Mass Storage devices
sr0: scsi3-mmc drive: 62x/62x writer dvd-ram cd/rw xa/form2 cdda tray
Attached scsi CD-ROM sr0 at scsi0, channel 0, id 0, lun 0
Attached scsi generic sg0 at scsi0, channel 0, id 0, lun 0, type 5
atleast when i atach my USB2 DVDwriter, should look something alike for you.
the writer is sr0 as you can se above.
also
Code:
 fdisk -l
will list the partitions available for you.