Howto:
LiveUSB
1) Download the latest live image. You can download it from the official Fedora mirrors.
a) Fedora 15 Live Images – Live Images for Fedora 15
2) Download and install LiveUSB Creator.
a) Windows – LiveUSB-Creator
b) Linux – run su -c yum install liveusb-creator -y
3) Install the LiveUSB Creator program.
4) Insert the flash drive you want to LiveUSB to run on.
5) Open the LiveUSB Creator Program.
6) Browse to the folder you saved the Live iso image to in step 1).
7) Select a size for the persistent image. I use 1024M.
8) Click on create now.
Go grab a cup of java. This part can take up to 15 minutes. When it completes, you have a boot-able LiveUSB drive.