Hulu on an iPad? How about Photoshop, or FarmVille? While all of these are technically possible thanks to the Air Display app, they're not all recommended, or even viable. But yes, they can be done. So can using the iPad as a wireless tablet interface for graphic or music applications.
How to turn your iPad into a second monitor for your Mac
You will, however, need a Mac running close by.
Many owners of iPads, myself included, have noticed how the device actually works quite nicely as a "second screen" when placed next to a home computer. Air Display takes the metaphor literally, by enabling the iPad to become an extended desktop display for your Mac.
Air Display works over local Wi-Fi, with the aid of software that's installed on any Intel Mac with OS X 10.6 or later (Windows support, says maker Avatron, is "coming soon") and toggled via a toolbar. The setup is dead simple: First, launch Air Display on the iPad. Then, enabling Air Display on the Mac shows a list of whatever iPads happen to be on the same local network (odds are, just the one you're using, unless you're at an Apple Store). Click the name of your iPad, and you're set.
The extended display activated fairly quickly, and worked just like a second monitor does: We were able to drag any window on our Mac onto the iPad. While the reaction time was quick, unlike the several-second lag that occurs on Intel Wireless Display-enabled computers, there was a noticeable framerate drop on secondary display functions. On version 1.0, the image sometimes broke up or clipped oddly as well--the technology at work is not unlike what enables you to use your computer remotely via VNC.
There is a nice surprise, however: Touch-screen controls do work. We could tap to click links in Safari and to browse, although the mouse cursor tended to leap from point to point instead of smoothly dragging. We even were able to drag a window and highlight text, though that was a bit hit-or-miss. Continuous motions such as drawing on-screen work better. Still, even in its first release, touch works nearly as well as any Windows 7 tablet PC we've seen. And, windows had the sense to auto-expand to fill the iPad's screen space properly--maximizing anything from Safari to GarageBand was easy to do whether we were in landscape or portrait mode.
Well, so now that the iPad can be a Mac extension, what exactly would we do with it?
Our first instinct was to load up Hulu, of course.
And yes, it does run, but audio does not carry through. Air Display is video only, so you'll need to run audio through your Mac's audio-out or built-in speakers. Video did stream, albeit more at Netbook speed. Full-screen viewing deteriorated into a slideshow. For comparison, we half-dragged a streaming episode of Hulu between the spring 2010 MacBook Pro and the iPad.
Hulu via Air Display: iPad vs MacBook Pro
Streaming is fluid on the MacBook Pro, and choppy but watchable on the iPad. And, again, the audio is coming from the MacBook Pro. But, it's a nice trick, isn't it?
Of course, Air Display isn't meant to be used for video, or even games. It's meant as a second display for e-mail, documents, or any graphic information that wouldn't need animation or rapid motion. To its credit, the refresh rate is fast enough to try Hulu--previous wireless-monitor solutions never approached that level of speed. It could also be handy to run more static Web apps, such as Google Docs. It is a clever solution in that regard. But you'll need a dock or a case that can elevate your iPad to an appreciable height to use it properly. Our Apple case worked in a pinch.
There is one caveat: We're not sure an iPad even needs to be used as second monitor in this respect. You can use your iPad as a "second display" without physically linking it to a computer--as a dedicated e-mail window, or a Web browser, or for information such as weather or stock prices. Air Display is really best considered a way to extend a workspace that might need instantly connected applications, such as multiple Word docs.
The publisher says the current version does not support direct Bluetooth keyboard input and is meant as a display extender only, but future versions may add support to turn your iPad into a true remote terminal in your home. That could be a great solution for home users who want to turn the iPad into a second computer--literally. Incidentally, it's also a step closer to the sort of drag-and-drop seamless interface between tablets and laptops that we've seen in everything from Avatar to Minority Report.
As it stands, $9.99 is a cheaper investment than buying a second monitor on top of your iPad, but don't expect Hulu-playing miracles. Yet.