yup, if ur bios supports usb booting. I'm doing exactly that with slackware 10.2.
Install like you normally would except make sure usb support is compiled into the kernel or you can use mkinitrd (requires initramfs kernel support) to make initrd.gz images to load the usb modules. The first option is a better one in my opinion.
also add
Code:
append="rootdelay=8"
to your lilo.conf or menu.lst file, (lilo,grub)