A few years ago, this particular Pratchett fan in California found the Science of Discworld books on amazon.co.uk when I was given a gift certificate from an anglophile friend who already knew what I was about to discover: that some truly wonderful things are available in the UK that are inexplicably absent from American shelves. Now those books are to be had through amazon.com (I guess due to the “international edition” being published last May), but before finding them on the British site I’d never seen them anywhere in the States (I guess 'cause we love our Intelligent Design so much out here in the hintercolonies). I’m gonna go ahead and pay extra to get Raising Steam now from amazon.co.uk.
'Cause it’s never not been worth it, AFAIC.