This article tells you how to Remotely Control Wirecast with an iPad, but I like the part where is shows how to Switch Shots on Wirecast With Keyboard Shortcuts:
Wirecast has built-in keyboard shortcuts to switch between your “Shots”. The trick is to name each shot with a number at the beginning, for example “1 Main Camera” or “2 Remote Skype Video”. Then by holding the Option key and pressing the corresponding number on the keyboard the shot will be activated. Combine that with making sure “Autolive” is selected and when you press the commands the shots will switch on the fly.Press OPTION 1 for camera 1, and OPTION 2 for camera 2.