The European Union is a fair way down the road towards requiring companies outside the EU to account for EU VAT (sales tax) on digital content sold into the Union - this affects you if you're running a paysite. I've written a summary, which you'll find at
http://www.netdialers.com/articles/eutax.html along with links to the full thing and some stuff about what a great bloke I am..
Cheers -- Dave