ScreenPad is a thin client that allows an iOs touch screen to be incorporated into desktop apps. This can act both as a second screen and as a more intuitive form of interaction with desktop software. Developers only need to add a few extra lines of code to their app to get started with ScreenPad. Its also possible to use ScreenPad purely as a thin client to a server, so that custom content can be served to a number of iOS devices on the LAN.
To use ScreenPad, simply run a supported desktop application, then start the iOS app. The two machines should find each other on the LAN, indicated by the ScreenPad turning from red to green, and then it should just start working.
A remote webcam viewer is available from http://www.dctsystems.co.uk/Software/ScreenPad.html which allows you to view you Macs webcam using ScreenPad (for example as a babymonitor, or security app). It also includes source code to make integrating the touch screen into your own program as simple as possible. The support page also includes source for an iOS webcam broadcaster, so you can send images from your iPhone to screenPad, or incorporate ScreenPad support into your own iOS app.