I am currently running DuoLingo on the browser on my Android tablet, which works fine but is a little clunky. I believe that DuoLingo would have a greater impact on its target audience if it released an app for both Android and iPhone. Thoughts?
Personally, I think duolingo should release a public API to interact with the site, and then if they are short on time, a 3rd party could manage the iPhone and Android apps. If they ever released an "official" app, then people would have the option to use that or stick with the 3rd party one. I guess if they wanted to force people to use their app, then they could change the API.
You should have a look at their twitter, they are pretty active: http://twitter.com/duolingo/status/253587125759520769
That is the iOS version, and I remember reading that Android was next after that.