Recently I downloaded Red Hat Enterprise Linux 6.0 to install on my home server. And I'm a person who haven't used Optical Drive for ages. On my laptop even DVD Drive doesn't work properly. So every time I use USB Drive (Pen Drive) to install any operating system because my server doesn't have a optical drive. Although I call it a server it is just a machine without CD Rom and blah blah.
Then as usually I wanted to make Red Hat ISO bootable. Then I used UNetBootin to make my USB drive bootable. But I got mounting error in installation when I was going to format hard drive. So it never happened with Ubuntu for me. Then I searched here and there to find a method to install RHEL. Then I found a link to iso2usb. It worked bit far away from that place. But it just installed minimal Linux server with out any GUI. There was no any option for it on Installation Wizard. Installation Wizard was GUI one although.
The I used fedora live usb create. It didn't work properly. Then I copied all the contents of DVD into my server machine and added a repo entry for yum to DVD packages. :)