I've e-mailed SMART Technologies (I'm a certified trainer for SMART Notebook and SMART Response) about the possibility of an iPad app. I actually tried calling first, and no one there wanted to discuss the possibility.
My fear is that the thoughts shared earlier on this thread are accurate: SMART will not make a Notebook app for the iPad with the fear of affecting their sales of SMART Boards, Sympodium units, and Airliner Slates.
Apple recently opened up VGA out capability to various iPad programs, including PaperDesk, as close an alternative to SMART Notebook as exists at the moment. However, you still can't import objects or interact with objects in these programs. I'm sure the iPad can handle these tasks (as seen with Keynote for iPad), but the programmers haven't caught up yet.
And, as we're all aware...no Flash on the iPad. And most of the interactive gallery for Notebook consists of flash modules.
As for iPads, one of the nice features is that the VGA out has worked flawlessly on every projector I've connected to. Even my MacBook struggles from projector to projector.
Two things are going to happen: First, districts will consider the cost of a SMART set-up (computer, SMART Board, Projector, Sound System, and installation) to the use of an iPad (or other slate) with a mounted projector and sound system. Districts could theoretically save $6000-$7000 per "intelligent classroom" by going with an iPad and mounted projector. That even considers the purchase of an iPad keyboard for each teacher. (I've found that the iPad works well with management programs like Infinite Campus, online programs like ClassJump, and for most teaching needs, Apple's iWork suite would be more than adequate).
Second, wireless video will settle on a standard and eventually be placed into most devices, including iPads. At that point, the Interactive White Board movement will fade away. The problem with many IWBs is that they are connected to the front of the room, and that they are a single touch device (there are some IWBs that are multi-touch; but SMART's model is based on single touch, even on the new 1/2 and 1/2 boards).