"Apple is strongly encouraging developers to make a single binary that runs on both the iPad and the iPhone, so called universal applications."
"Apple has also said that existing iPhone applications will run on the iPad and that they will be able to be “blown up” in size to be full screen. From reports I’ve heard and my own experience in the simulator, this doesn’t look very good. Developers will want to have an iPad specific interface built into their app. The amount of work to get an iPad app’s UI to have the great polish it should have is going to exceed that of the iPhone. This will mean higher development costs. Presumably with higher development costs, higher prices will come with it. The rub is that these universal applications are going to be subjected to the same price pressures from the iPhone side of the market because users will buying a single binary."
The entire article can be found here (the comments are good too):
It will be interesting to learn how this all shakes out in time. Will we typically see one universal app, separate iPhone and iPad apps, or all three (i.e., universal, iPhone-only and iPad-only apps -- presumably at different price points)?