You need a Linux installation image, e.g. SUSE-Linux-10.1-Remastered-i386-mini.iso. You can download this from a openSuSE mirror server.
The package syslinux must be installed to make a bootable USB stick. So if you haven't it installed you must do so now.
Asume your USB stick is accessed with device name /dev/sda1, you can use the following commands to write the image to the stick and make it bootable:
umount /dev/sda1 mount -o loop SUSE-Linux-10.1-Remastered-i386-mini.iso /mnt /mnt/boot/i386/mkbootdisk --32 --partition /dev/sda1 /mnt