Rufus is a free and open-source software that can be used to format and create bootable USB drives or Live USBs easily and quickly for Microsoft Windows. The free tool (Rufus) allows you to format your flash drive or card to FAT32, FAT, NTFS, UDB, exFAT, and more.
All versions of Rufus since v1.1.o, allow the creation of a bootable USB from an ISO image (.iso). Creating an iso from a physical disk or from a set of files is very easy to do however, through the use of a CD-burning application, such as the freely available InfraRecorder or CDBurne.
License
GNU General Public License (GPL) version 3 or later. You are free to distribute, modify, or even sell the software, insofar as you respect the GPLv3 license. Rufus is produced in a 100% transparent manner, from its public source, using a MinGW32 environment.