How to create Bootable USB Key?

I am trying to create a bootable USB Key and I can't seem to find any real information about this at all.  I see several posts that point to http://www.memorykeytools.com/ but it seems to no longer host the utility necessary to create a bootable USB Key.  It states that it is on the Resource CD but I can't find it there either.  On top of that the page is short on details as to how to actually go about creating the bootable partition and setting up the system files.  If anyone could help me with this that'd be great.  I'm trying to replace my current MS-DOS boot floppy with the USB Key.

TC