Mobile phone app

What I need is a mobile signal sending device. The mobile phone user clicks a button, and a signal will be sent to a remote PC. The primary requirement is that the transmission be as fast as possible - even a few 100ths of a second will make a big difference to me. I need a developer who understands the different ways of sending this type of signal (the various mobile platforms and signal types) and can choose the fastest method. ## Deliverables As I said above, my main requirement is that the signal reaches the remote PC as fast as possible. The PC will be based in the UK, and the mobile device may be in the UK or overseas.