UNetbootin is a cross-platform utility that allows users to create bootable Live USB drives for various Linux distributions and other operating systems. It supports a wide range of ISO images and can create bootable USB drives with a variety of filesystems, including FAT, NTFS, and ext4. The software also includes a built-in downloader that can automatically fetch the latest ISO images for various distributions. Additionally, UNetbootin can be used to install Linux on a hard drive alongside an existing operating system.