While I’ve used OpenStreetMap data before, I’ve never added anything to it. That changed after going to Mappy Hour last night, and meeting Richard Weait. He has a bunch of useful tutorials on his website.
I’m rather taken with the symbol that Japanese maps use for wind mills and wind turbines. I’ll try to modify it for use in QGis.
Update: so how does this look?
I cleaned up the blade angles, added line end-caps, and made all the white bits transparent. Works fine in QGis.