Hardware wise they are identical, it's a software setting (which will be hacked by the guys on XDA-Devs in pretty short order).
Once volumes are available and Vodaphone Uk have everything sorted out I suspect there will be a choice on Googles own store to buy a UK/European handset, with the software change and shipped from within Europe with taxes included.
Devicewire, Expansys and Play.com all have pages for it though. I still wouldn't be surprised to see it available from other retailers in due course.