Go to UNetbootin's home page: http://unetbootin.sourceforge.net/UNetbootin allows you to create bootable Live USB drives for a variety of Linux distributions from Windows or Linux, without requiring you to burn a CD. You can either let it download one of the many distributions supported out-of-the-box for you, or supply your own Linux .iso file if you've already downloaded one or your preferred distribution isn't on the list
The site lists these as currently supported OS's in either single or multiple versions
Get the full current list of working OS's at: http://unetbootin.wiki.sourceforge.net/ ... tributions.* Ubuntu * Debian * Linux Mint * openSUSE * Arch Linux * Damn Small Linux * SliTaz * Puppy Linux * FreeBSD * NetBSD * Fedora * PCLinuxOS * Sabayon Linux * Gentoo * Zenwalk * Slax * Dreamlinux * Elive * CentOS * Mandriva * FaunOS * Frugalware
While I don't think this is an application with a common everyday use it is AFAIK portable and could be used at least for its stated purposes with a Flash drive to create a live USB.
I also did a search before posting: http://portablefreeware.com/?q=unetbootin&m=Search, and: http://portablefreeware.com/?q=universa ... r&m=Search.