Create bootable Snow Leopard USB drive/stick from Ubuntu
If you have the install DVD or an .ISO rip, you can use the dd command to write it to your USB drive.

sudo dd if=~/osx-snowleopard.iso of=/dev/sdb


Just replace "~/osx-snowleopard.iso" with the path and name of the ISO file and "/dev/sdb" with the device node name of your USB stick.  

Use the lsblk command to figure out which device name is your USB stick.  It's probably going to be sdb or sdc.  If your geek stick automounts when you plug it into Ubuntu, make sure you unmount it first; just right click the USB stick's partition and click "Eject".