WinToFlash Lite is an easy-to-use tool which will quickly create a bootable USB flash drive version of your Windows installation disc.
This could be very useful if, say, you need to install (or reinstall) Windows on a netbook, or any other system which doesn't have a working optical drive. Or if you manage a network and are always reinstalling Windows, for instance, doing so from a USB flash drive rather than a DVD could significantly speed up the installation process.
If your needs are basic then this is all surprisingly straightforward. Essentially you just have to point the program at your installation DVD, and the flash drive you'd like to use, and that's about it: WinToFlash handles everything else for you.
Switch to advanced mode and you're also able to create Windows PE, DOS or other bootable environments, as well as making low level tweaks to the file system and elsewhere.
And note also that this version is free for non-commercial use only, and includes ads. These are fairly unobtrusive, but if you like you can purchase a personal licence to remove them (current cost is $5.77); a Professional licence ($29.95) adds more functionality, and commercial use requires the purchase of a Business licence ($100). See the WinToFlash site for more.