If you’ve just got a computer or two to update I’d suggest just finding it via Windows Update. If you’ve got a whole bunch you can download the whole shebang, burn it to a CD, and install it that way.
"You Two! We're at the end of the universe, eh. Right at the edge of knowledge itself. And you're busy… blogging!" — The Doctor, Utopia
If you’ve just got a computer or two to update I’d suggest just finding it via Windows Update. If you’ve got a whole bunch you can download the whole shebang, burn it to a CD, and install it that way.