Even though the first iPhone lacked a GPS and compass (not to mention a true gyroscope), there were a few early avionic entries to the App Store, mostly involving crude tilt measurements. When the iPhone got a GPS and then a compass, it became a wee more useful to the flying sort. The iPad brings ample screen size to the table, and the iPhone 4 has a gyroscope. But leave it to good ol' American ingenuity (or largess) to put an iPad smack in the middle of a plane's dashboard.
The iCub is a small bush plane with an iPad mounted inside. According to Bill Canino, president of SportairUSA (makers of the iCub), the iPad is more of an accessory than an actual flying instrument. For one thing, it isn't FAA-certified. I doubt any sane pilot would rely on an iPad to actually fly or land a plane. Canino's suggestion, made clear by the selection of apps they will include on the device, is that the iPad is a companion to the plane's occupants. If you land on a beach and are injured, now you'll have the resources available to know how to sew that arm back on. Bush planes don't usually incorporate hi-tech devices, so the iCub hopes to set itself apart with an interesting set of apps that might be useful to the folks who fly these particular planes.
I asked Canino how they were going to load the apps and they were still working on that process but it will allow end users to own the apps, probably by setting them each up with an iTunes account (if they don't already have one) and gifting them the apps. There are still details to be worked out, but if you're in the market for a new bush plane plus iPad, you can go ahead and order an iCub today for the low, low price of $92,900 -- slightly more for the Bush iCub model.