I put Knoppix 5.1.1 on a 4 Gb flash drive using the tutorial found at www.pendrivelinux.com (choose the Knoppix USB tutorial) It took me about an hour, 45 minutes of that was downloading the zip file you have to extract the the USB drive. You only need a 1 GB flash drive according to the site. It's very nice I'm using it on a Dell Lattitude D410 with the centrino chipset. I like it much better than XP.