I covered simple texture mapping - affine mapping on a 3D rotated plane - in my previous post. Mapping a texture on a sphere is of course more difficult. In this post I present two Python solutions, which both are less than perfect. Also, you may want to take a look at the RGB Sphere I wrote about earlier, with more spherical 3D graphics, using polygons - it maps a world map on a sphere as well, with light sourcing, although the resolution is then quite low.
As usual, the code can be found in my github repository.