DisplayLink has released software to use your Apple (NASDAQ: AAPL) iPad as an additional display with your Windows machine--over Wi-Fi. Released just last week, the iPad app can be purchased here for an introductory price of $1.99. Having used the company's USB-to-video adapters, I immediately purchased the software and downloaded the free host software. Connecting was a snap, and my iPad appeared as another 1024x768 monitor--with full Aero support. There are some downsides to version 1.0 of the software though: It only works with Windows, and unlike similar solutions on the market, does not support touch input on the iPad. See more on DisplayLink.