Cloning Hard drive to USB Flash drive

Is it possible for me to clone the hard drive of my Macbook mid 2009 5'2 running OS X 10.5.8 safely onto a USB storage device? I have used about 28GB of space on my macbook and want to Clone the hard drive in case anything goes wrong in the future, I have a 32GB USB drive.

I want to be able to boot up from the USB also, I understand that you can do this process entirely through disk utility and that you have to format the USB to MACOS Extended Journaled. But can someone help me on the rest of the process a detailed description or a link to a video or webpage would be really appreciated. Thank YOU