Hi darkowlzz ,
There are two ways two think of the interaction between the Arduino and the IOS.
Option 1: A wired interface where in the IOS device is connected to the Arduino .
Solutions in the form of cables are available out there that can help do that http://www.makershed.com/Redpark_Breakout_Pack_for_Arduino_and_iOS_p/msrp02.htm
Option 2: Wireless connection between IOS and Arduino via a bluetooth or a wifi connection
You could think of some solutions like a Arduino UNO + serial bluetooth modems that sets up the arduino side of things or try a Arduino + a wifi shield that can provide a wifi connectivity.
Hope this helps !
Feel free to post in additional clear requirements if you have something specific in mind.