I'm interested in developing an android app that makes use of an OpenCV android port at http://code.google.com/p/android-opencv/. Particularly, I want to use SURF features which comes embedded in the OpenCV framework but I'm not sure if then I will be able to sell this app.
Anyway, is there any non-free app making use of any of the OpenCV android ports?
Read the license files of the particular port you are using.
The two different ports I googled and looked at in the past two minutes seem quite clear.
SURF is a patented algorithm. You need permissions to use it in commercial applications. SURF comes with OpenCV because there its being used for "academic" or "research" purposes, without any commercialization involved.