Bought it from the US steam store...it works for the UK Steam store as well.
You have to 'trick' the online store into thinking your a resident of that country, so when you log back into Steam, it will download the appropriate version. Credit card payment is a must as I am unsure if it works with a Paypal account.
If you want to know how, you can google it, or, I can post up how I did it.