Sergey Sharybin added sphere and tube mapping options to the image node yesterday:
[12ccac6] Cycles: Support sphere mapping for the image texture
[dda3554] Cycles: Support tube projection for images
What is it?
Just the same mapping types we’ve had in BI for years ;)
Sphere mapping allows us, for example, to painlessly map a texture of the Earth onto a sphere without needing to do any UV mapping.
How do I use it?
Simply change the projection method on you image node from Flat to Sphere or Tube, and probably you’ll want to use generated coordinates.