I just searched Yahoo for "booting windows thumb drive" and several methods came up, the first 2 hits from Tom's hardware and Information Week magazine which should be reliable sources.
Yeah, sure...those techniques are written by some hacker, require extra software, and don't have the support of the vendor (i.e., Microsoft).
Why would I want to waste my time on such nonsense when I can get a Linux distro made specifically to run from a USB drive?
Now you're advocating the violation of Microsoft's Windows license? There is only one live CD/flash version of Windows that's legal according to Microsoft, and that's Microsoft's own WinPE, available only for enterprise use.