Hurry though - most of the retailers are now showing it to be out of stock, especially at the prices advertised. Also the UK MS Store has been permanently down (overloaded) since around 8 am. There has been a huge interest in Windows 7 at the pre-order price for virtually everybody to be sold out. Amazon seems to flicker between out of stock and available again according to reports which I have read - could be that they are constantly getting back in contacting MS and pleading for more copies.
At this rate the UK will be the same as Japan and pre-sell all of their special pre-order versions on the first day. Get in quick before you lose the chance, but it may already be too late.