I’m working on a project right now where Linux on a USB flash key drive would be very cool! I hunted around a little bit and found these directions. These directions worked out really well with one small correction to a dead link for “Syslinux”, here’s a corrected link. I downloaded the lastest version of DSL here. I used a Corsair 1 GB Flash Key Drive like this one. Good liuck with your USB bootable flash drive, they’re great!