The CyBook isn't out yet, so you can't buy one of those.
The only company anyone appears to have discovered which will ship the Sony Reader internationally is:
http://www.bhphotovideo.com
They charge $298 for the Reader, plus a cheapest shipping method of $46, so that's a total of $344, or about £170.
Do bear in mind, however that, as I said before, when it arrives in the UK you're going to have to pay 7% import duty, plus 17.5% VAT, which is about another £44, plus possibly a £10-£20 "processing fee" depending which delivery service it ends up with when it reaches the UK.
ie you're looking at a total cost of about £230-240, or approximately US$470.
Sorry, but that's the way it goes.
You
may be able to find one a little cheaper on eBay, but obviously that carries its own risks.
Good luck - there are many of us on this forum who have bought Readers from the US and are very happy with them.