I'd like to be involved in producing "cookbook" style documentation and longer tutorials; in particular, I can help with stuff about the C side of the MeeGo platform (especially Clutter, but also various GNOME-related bits and pieces); and I'd be interested in learning and documenting Qt, particularly the web-related parts of it (QML and Qt Web Runtime) as my background is mainly in web development. One example might be documenting how to use libraries like jQuery UI in a WRT application.
I could probably also assist with SDK tools documentation (how to set up Xephyr and Qemu, Qt Creator etc.). However, it may be better for someone else to do this, as I'm not so closely involved with it these days.
At the moment, I am working mainly on the Clutter cookbook.
From various discussions on the mailing lists, I'd guess that the following topics are most desperate. I'm not sure what documentation already exists for all of them.
Platform and app development (meego-dev and forum.meego.com)
(I actually personally find it quite hard to work out where the line between the platform and app development is.)
SDK tools (meego-sdk)
The SDK topics seem to be less because of documentation gaps and more because of SDK missing features, bugs, and hardware incompatibilities.
From discussions on Qt QML list, it appears as though getting started is well-served by existing documentation. The questions don't fall into easily-segmented areas in the same way the MeeGo platform issues do.