There are other sites that sell ePubs. Two off the top of my head are:
http://www.diesel-ebooks.com/
http://www.smashwords.com/
As to the geo-restrictions... I think the site knows where you are from and keeps you from purchasing a book that's being restricted in your area/country. For instance, if I can't download the ebook versions of some of David Eddings' books, but people in the UK can. It is of the stinky.
I'm sure someone more knowledgeable on both points will chime in soon.