The ISO file includes a file called usb-creator.exe in the CD image. You need to run this program, so you need to copy it out of the CD image. To do so, you can burn the Ubuntu ISO file to a disk, or you can use a Windows utility such as Virtual Clone Drive to access the .iso file's contents. You can also use 7Zip to extract the ISO so you can work with the files inside.
This process is described in detail in a video on this website.
Once you have usb-creator.exe, run it and follow the same steps as described for Linux (point it at your .iso file or your Ubuntu CD-ROM, point it at your USB flash drive, make sure you have the right device selected, then "Make Startup Disk").