I think I tried somehting similar, something called a UNetbootin? I can select a distro and version, but I am just getting errors every time I boot from that..
From what I can tell, FreeNAS is what I want. But I am just having problems installing it onto a USB.. Not having a cd drive in the pc isn't helping.. lol.. Thanks everyone for the responses so far!
But in unetbootin, where it says to select the ISO. There is a drop down that will say "floppy" click that and then select the .IMG file. It should work perfectly.