Sorry, Ken, but it's been over six months since my original post in the Forums Feedback forum about this on 2010-03-10, 12:54 PM. That's too long a wait.
As I said in that update, we've finished the basic work of being able to read and view and edit and save outlines (months ago, now)—but creating a great touch-based interface for text outlines is not an easy problem and we're still working through plenty of design issues (the latest being how best to simplify local hierarchical styles).
Some of these design issues aren't necessarily new to the iPad—the styles interface was certainly already quite confusing in OmniOutliner 3 for Mac! But we didn't want to carry over confusing concepts just because they were on the Mac; we think now is the best time for us to really rethink some of these problematic concepts, and the solutions we're finding are also helping us improve the upcoming Mac app.
I understand your anticipation: I've been wishing for an iPad version of OmniOutliner since long before I actually got my hands on an iPad. But it's our biggest design challenge to date, and I think it's important for us to take the time to get it right.
So as I've said in each of my iPad or Bust! posts, please don't rely on things happening exactly according to any particular snapshot of our plans. The reason we've shared our plans is not to suggest that anyone wait for any particular date; it's so that you'll have some insight into what we're doing and why, making it possible for you to decide whether we're going in a direction you're interested in.
In the meantime, enjoy OmniOutliner on your new MacBook Air!