IMO the best way to install the drivers is to get OS X Lion and download the drivers by using the Bootcamp assistant and then copying those drivers to some other device that can be read from Windows without any additional drivers. Such devices are usb sticks, external hard drives or for example android mobile phones that support usb storage mode. The device should be formated with either fat32, exfat or ntfs filesystem in order to read it in Windows. You can of course also burn those drivers to 700mb cd-r(w).
I wouldn't recommend anyone to use Snow Leopard disc to install the bootcamp 3.0 drivers since they are very very very old and do not support the newer hardware. Remember, when Windows 7 officially came out, Snow Leopard was already released, so the drivers weren't officially even Windows 7 compatible. While Windows 7 was fine with Vista drivers too, there were some compatibility issues and some people were unable to run Windows in 64bit mode.
I remember having some strange issues with my bootcamp 3.0 drivers when I first time installed Windows 7 on my 2009 13" macbook pro. These were mostly related to WiFi and while the drivers did improve later on with the updates, but they were never as good as the 4.0 drivers are out of the box.