Python for Nokia S60 platform becomes more and more mature. I guess you might start considering it as a tool for commercial applications already.
Check out the set of tutorials on Python for S60 by Jurgen Scheible, yet another Forum Nokia Champion. There are examples on UI, camera, networking, graphics, etc. And also on how to make the stand-alone S60 application in Python.
And by the way, if you know any commercial S60 application written in Python, please, post a link to the comments. I wonder if PyS60 is already a tool for earning money.