Yes, they're available in the UK although the page on UK pricing seems to have disappeared from Apple's site.
From memory, the smallest size are £3 (but you have to order in multiples of 3 so £8.99), the medium size are £8.99 (?or around that) and the large size are £14.99 (softcover) and £19.99 (hardcover).
That gets you 20 pages (10 doublesided) and the additional pages are charged at a differing rate depending on book size. Postage is extra - it's about £2.50 for the large soft book or £4.99 for the large hardcover book.
Cards seem to be about £1.15 each (reduced by 10p when you get to 25 cards) plus £1.60 postage.
Prints start at 15p for a 6x4 and go up to £1.69 for an 8x12 - postage is £1.99 regardless of number of prints.
Calendars are £11.99 for 12 months plus £3.99 postage
The books (all that I've ordered) look very good and everyone that I've given one too has been very impressed. They take about 10 days from uploading one to having it delivered