I don't either... it just happened!
I opened a new account with them when I placed the order at 6pm, received an acknowledgement within 5 minutes, and then the second email (well 2 actually) about 10 minutes later.
It definately says "We are now preparing your PC ***** order for delivery ." and a bit further down... "Your products will be prepared for dispatch and a further e-mail will be sent when we have your parcel tracking number(if applicable).
It all sounds quite hopeful to me, but of course, it hasn't actually been despatched yet!
Edit: As you managed to order one so early, I assume you went for the 16GB model? By the time I came home and checked the sites they were only offering the 32GB 'bundle', so that was the one I ordered.