Attainment Switch
This app from Attainment allows you to operate switch-accessible software with your iPod and iPad, creating switch access to the computer without the use of a switch interface or switches with cords. To make this work, you need access to a wireless network. Purchase this app from the App store, and then download software for your PC or Mac from the Attainment website. You can set up one button or two-button switches on your device, and can upload pictures to place on the buttons.
Requirements: Compatible with iPhone, iPod touch, and iPad. Requires iOS 3.1.3 or later