MaxComm is a free customizable controller for sending OSC messages to another computer over a Wifi network. The app includes an interface builder, which allows the user to add sliders, buttons, and toggles. Interfaces can be saved, loaded, and exported as max patches for use in Max/MSP. MaxComm allows users to send motion data (using the device's built-in accelerometer and gyroscope) as well as multitouch data. MaxComm was designed for use with Max/MSP, but should work with any program capable of receiving OSC messages via UDP.

Get the app here: iTunes 

MaxComm normally requires the user to manually enter the host computer's IP address. However, I wrote an abstraction that will send out the host IP when it is sent a bang message. To use the hostIP abstraction, open the connections view in MaxComm and send a bang message to the hostIP abstraction.

The hostIP file is here: hostIP

Select and copy the text, open Max/MSP, go to File, and select "New From Clipboard".