You *DO* need to have the LiveCd? ISO file, but no need to burn it to CD.
Be sure that you have checked the MD5 of the ISO before running.
If you are running Windows, you can install VMWare Player (free):
I've zipped the VM for easier up/download, so you'll need to unzip it:
This is UNTESTED so YMMV, but "works for me" on MBP running Fusion 2.xx