Apple provides some tools along with detailed step by step guides to help you install Windows for a dual boot setup on your Mac, but even if you follow them completely, you may find yourself stuck (as I was) very early in the process because the Windows Setup program can't find the drivers it needs to continue, even though they were so carefully prepared by the Bootcamp assistant. I tried preparing my bootable USB drive with 3 separate Windows 7 x64 ISO files, and could never get past this 'No Device Drivers found' error. In retrospect this could have been because the only USB stick I had that was big enough was a USB 3.0 stick and the USB 3.0 drivers needed to access it were on the stick, so in true Chicken and egg fashion Windows setup needed the drivers in order to find the drivers... So using a USB 2.0 stick might have resolved my issue.
However, while I didn't think of that at the time, I was still able to get Windows up and running: By inserting the original Windows 7 install DVD, rebooting the mac, holding down the option key to boot from the windows disc I was able to install Windows successfully. Of course, most of the hardware wasn't working due to missing drivers, so after windows setup completed, I returned to my Windows PC and burned the entire contents of that USB stick to a DVD-R. Inserting that disc I was finally able to run the Bootcamp setup that had been so lovingly prepared by Apple, and installed all of the drivers I needed to make Windows actually work.
Making the DVD-r bootable would have been even better, but since I'd already installed Windows by that point I didn't need to. (I used a $25 external USB 2.0 optical drive, since my Macbook Pro didn't come with an one).