It really is simple, once you know what to do, of course!

sh-3.2# diskutil unmountDisk /dev/disk1
Unmount of all volumes on disk1 was successful
sh-3.2# dd of=/dev/disk1 bs=1m if=debian-6.0.6-amd64-netinst.iso
168+0 records in
168+0 records out
176160768 bytes transferred in 84.783919 secs (2077762 bytes/sec)
sh-3.2# diskutil eject /dev/disk1
Disk /dev/disk1 ejected

 

Good times!