This page presents:

• Scripts
  • A script, ubcd2usb-linux, that allows you to convert a UBCD .iso into a bootable USB thumb drive. To use it, loopback mount a UBCD iso somewhere, and then run the script pointed at that loopback mount. Usage is described at the top of the script.
  • If you're stuck with windows, you can use this instead.
• One such UBCD version usable on a USB thumb drive, in case you don't want to use the script. It's a 1 gigabyte image (but it's compressed), and it's a mix of UBCD 3.4 and 3.3 (preferring 3.4), because it appeared that some things I wanted to use had been been only partially put into 3.4, but were fully there in 3.3. To use it, you can use something like:
  gunzip -c ubcd-usb-34-and-33-merged.gz | dd bs=1024k of=/dev/sda
  ...but be very careful with the of=/dev/sda - if you specify the wrong device, you will lose data! Also, you'll lose the data previously on your USB thumb drive whether you make a mistake or not!