You can burn the iso file onto a DVD and use it to install Windows on a Mac with Bootcamp. Disk Utility can burn any image or files you want to CD/DVD so you won't need to use a Windows computer to burn the disk image. Here's an article for that
Mac Tip: How to burn an .iso or .dmg file to disc... and on further review I just found this on the manual for bootcamp for Lion.
http://manuals.info.apple.com/en_US/boot_camp_install-setup_10.7.pdf
"You may be able to install Windows 7 with a USB flash drive that contains a Windows 7 ISO
image downloaded from Microsoft. To check whether you can do so, open Boot Camp
Assistant, click Continue, and see if the option “Create a Windows 7 install disk” is available.
To install Windows 7 with a USB flash drive, you need the following:
1. An ISO image of Windows 7 Home Premium, Professional, or Ultimate downloaded
from Microsoft.
2. A USB flash drive with 4 GB or more.
Boot Camp Assistant erases the flash drive, and copies to it the Windows 7 ISO
image and software drivers that let Windows work with your Mac hardware
To see how much free space you need on your disk for Windows, refer to the
documentation that came with Windows.