Step One: Take the .ISO and use Disk Utility to burn the ISO to the disk. For more detailed instructions, refer to this:
http://hints.macworld.com/article.php?story=20060619181010389
Step Two: Open Boot Camp Assistant and follow the instructions on how to make a new Windows partition and
SHUTDOWN when ready.
Step Three: When the computer first turns on (grey screen, before Apple logo and spinning gear), hold the alt/option key on your keyboard and wait for your boot options to appear.
Step Four: Select the CD for Windows. There may be an "EFI Boot" or something like that, but select the CD icon for "Windows" and hit enter.
Step Five: The Windows installer will start up. Continue until you get to the partition step. Usually, you will have to reformat the partition as the Boot Camp Assistant created a FAT32 partition. Click on something that is similar to "Advanced Options" or something at the partition window and select your Bootcamp partition and reformat. You should then click the same partition that you just reformatted and let Windows install.