There are some reasons you might want to use a USB Flash Drive to install Windows Vista in a computer, I can think of 3:

• having the new OS in a small device ready to be installed
• as eUSB says, access speed and transfer rates are quite impressive with 30MB/s
• in terms of size – DVD > USB flash drive – in this case the smaller wins

This “How to Install Windows Vista Using A USB Flash Drive” is pretty simple, the first thing you need to do is buy Windows Vista obviously… the second step is actually buying a high-speed USB drive so you can get those amazing speed numbers and install Vista in less than half an hour, the third and fourth steps require more attention and some real participation on your part, but they are easy to follow.

• 3rd step - Format the Flash Drive
• 4th step - Copy Windows Vista’s DVD ROM content to the Flash Drive – use this command: xcopy d:\*.* /s/e/f e:\

Props to Kurt Shintaku for coming up with the tutorial - read the whole thing if you have serious intentions of doing this.