So far what have you tried doing?
The iDevice Guru
Either use a VPN or visit unblockus.com a smart DNS which recognises what country you want to be in, it's brilliant I use it all the time
A VPN service (vypr, strongvpn, overplay, expressvpn for example) will do what you need.
You basically connect your device (iPad, iPhone, etc) to a US VPN server, and once connected, it appears that your internet connection comes from that server. If you pick a UK VPN server, you can even use BBC's iPlayer.