makebootfat is a command line utility able to create bootable USB disks for Linux and Windows using the FAT filesystem and syslinux.
makebootfat is the most advanced tool available able to make bootable USB disks. It's able to autodetect/partition/format/populate the USB disk in a single step without any user interaction. It's also able to create disk images which are compatibles with all the three standards USB-FDD, USB-HDD and USB-ZIP at the same time.
Now go to Download.
makebootfat has also a SourceForge page (shared with AdvanceMAME).