The shop is based in the UK but they ship internationally and right now they have half price shipping on international orders until the end of June. I have already found some really cute stuff for both girls and boys.
Since the prices and sizes are not american here are a few guides to help you get what you need. They have a size guide on the website that you can find here. I like to use Google for my currency conversions. All you have to do is type in the conversion in the search field, i.e. "45 GBP to USD" and it will give you the conversion. Or you can use an exchange rate website like http://www.x-rates.com/.