UNetbootin allows you to create bootable Live USB drives for a variety of Linux distributions from Windows or Linux, without requiring you to burn a CD. You can either let it download one of the many distributions supported out-of-the-box for you, or supply your own Linux .iso file if you've already downloaded one or your preferred distribution isn't on the list.
This site is the home for the libusb project. It's aim is to create a library for use by user level applications to access USB devices regardless of OS.