Posted 07 November 2012 - 12:43
When you download and run the installer, you'll be presented with two main options - perform installation from the installer, or create an ISO image for mounting onto a USB pen drive or burning onto a blank DVD. Because of this, there's no real need for getting a shipped copy.
And yes, you can use PayPal or a credit card for the online payment.
Incidentally, to use the upgrade, you'll need a valid XP, Vista or Windows 7 installation. If you have a spare XP license, I'd install this first, then let the installer perform a clean installation over this.