If you want to create qt applications, there is an (outdated, but still instructive)
tutorial, that I used.
For KSM I used (instead of the materials referred to in the tutorial):
https://launchpad.net/linaro-toolcha..._linux.tar.bz2
http://www.mirrorservice.org/sites/d...c-4.8.5.tar.gz
Instead of QT_drivers.zip that is uploaded to the tutorial, I am using the drivers that are included in Sergey's KoboLauncher/PBChess.
Edit: For creating simple Qt apps for Kobo , the tool chain and qt is all you need.