You may know that the US version of Netflix has a lot more content than the UK version. I've found there to be a lot more movies on the US version, movies which don't seem to appear on the UK version. If you ever wanted to watch the US content you have to do a bit of configuring to do it and you can't usually do that on an iPad, iPhone or PS3.
UnoTelly is a neat little paid service where you can watch all the American channels you like through some minor DNS changes, which can be done on most internet capable devices.
UnoTelly let me try out their service so I could throughly test it - I must say I was pretty pleased.
You just aren't limited to watching Netflix though, you can watch a whole array of different channels from different countries. Including channels like ESPN, Hulu and LoveFilm US.
To get started you simply choose a price plan which fits your needs. You get a free trial at first so you can make the decision whether the service is worth your money or not.
Once signed up there are various tutorials on how to get your devices set up to watch content from other countries. It's fairly easy process which anyone can do. They provide text and video tutorials. If you still get into trouble, they have a support forum and a support ticket system where they will try their best to help you.
I've been using the service to watch all sorts of content, mainly Netflix though.
I do highly recommend it, it saves a lot of trouble and it's always ready.