The nice thing is, all you have to do is write an app in Qt. Aside from some screen size considerations, there is generally nothing different to do for a QT N900 app than there is for a desktop app. You just select a different compile target.

Here is a link to the wiki article I wrote on packaging Qt Creator apps: http://wiki.maemo.org/Packaging_Qt_C...r_Maemo_Extras
It may give you some help in getting your app out to the rest of us.