Yes, it's possible. I have Fedora 8 installed on a USB drive, runs quite happily.
Just run a normal install, but make absolutely sure that when it reaches the grub install that you tell it to boot from whatever your USB drive is listed as.
(I made the mistake of selecting the wrong drive once and overwrote the MBR of my Windows drive)
Once installed, enable USB boot in the BIOS and it should boot from the USB drive.
Originally Posted by lauwers
Why because I read that it possible to do so with PC linux
So I am wandering why it is not possible with Fedora 8
all the best