I'm in the same boat as the other international forum members in this thread. Swiss and wondering, whether I will be able to make a reservation for the 24th (when I'll be in London anyway). I do have have the Apple Store app and even a UK account if need be. I can not, however, provide a UK credit card.
I was planning to wait for a Swiss launch (site says '2015', very vague). BUT some Swiss tabloid has just revealed that a Swiss watch manufacturer got trademark protection for the name Apple in connection with watches ages ago. And that trademark is still valid.
Long story short: Swiss customers might be screwed (at least for a while). Of course it's a tabloid and it might be BS. But I've just checked and that trademark actually exists. So, guess if I want an Apple Watch, I will have to buy it abroad.