I too am interested in buying the british versions here is the link http://www.amazon.co.uk/Harry-Potter-Boxed-Childrens-Contains/dp/0747593698/ref=pd_bbs_12/203-7073628-7113524?ie=UTF8&s=books&qid=1187388316&sr=8-12
There are minor differences: the covers are all different; the title of the first book is different for the British version (The Philosopher's Stone vs. The Sorcerer's Stone); there are also many, many minor wording differences between the two editions (a lot of the British terms and phrases are replaced with American equivalents). Here's a website that will go over all of the major (and minor) differences between the two editions for you: http://www.hp-lexicon.org/about/books/differences.html
If you're really interested in buying the British editions, the easiest way is to buy from a Canadian store or dealer. Canada sells only the British version, and it's closer to the US and easier and cheaper to ship from Canada than from the UK. I myself read the British editions (my wife is Canadian and buys the Canadian books), and loved the British phrasings, etc.
Thanks for the HP Lexicon link. Didn't know that page was there :-).
Interesting to note: "Rowling is actively editing her books to fix errors and to adjust the story to fit the larger saga. As new editions of the books are released, these changes are incorporated into the text."
You can buy the British versions on amazon if you go to the bottom of the amazon page and click on the UK site. They have their own site just for Harry Potter books. The Box set is due to come out between 1-16 October of this year. There are two versions of the books, a children's and an adults version with different covers. From what some of my British friends tell me the adult versions are also longer with more detail after the 4th or 5th book.
I did notice continuity errors throughout the series, so I guess it's not so bad to be going back over them with a fine tooth comb, but I just wonder if the changes will include those mistakes I noticed, or maybe the ones I saw weren't mistakes at all, just character development?
One of my biggest gripes was with the Sirius Black character from book 4 to 5. In the 4th book he tells Ron that Hermione is correct about how house elves are treated, but then he goes and treats Kreacher like a blast ended screwt.
This is off topic, but does anyone have trouble with the scroller while trying to type posts? When I get a certain length the scroll bar jumps up away from what I'm trying to type. Anyone have that problem, and anyone know how to correct that?