Making a texture map for a sphere
 
 NOTE:  For the purposes of this exercise we will assume that you are using
 an image that either has (a) no alpha channel, or (b) an alpha channel that
 looks essentially like the original.  If your image has an alpha channel
 that looks nothing like the RGB image, you will need to repeat this process
 seperately on both the RGB and alpha channels.
 
 1.  MAKE YOUR TEXTURE SEAMLESS
 
 Open your texture image in Photoshop.  Run the OFFSET filter
 (Filter>Other>Offset) with the horizontal spacing set to approximately HALF
 the distance of the original image, the vertical spacing set to ZERO, and
 the WRAP IMAGE option selected.  By doing this you will literally push the
 pixels off the right side of the image and wrap them around to the left
 side.  This will show you a very clear seam in the middle of the image from
 what used to be the left and right edges.  The new textures wrap because
 the edge pixels used to be in the middle.
 
 Paint out the seam using the cloning tool, copying and pasting, and
 whatever other methods you feel appropriate to achieve the look you desire.
 You now have a horizontally wrapping texture.
 
 2.  MAKE THE IMAGE READY TO MAP
 
 When a flat image is mapped onto a sphere, a pinch point occurs at the top
 of the spherical map.  To get rid of this pinch point, use the LASSO tool
 to make a small, round selection in the center of the image.  FEATHER the
 edge 5 pixels (Select>Feather) and copy the selection.  Select ALL to drop
 the selection.
 
 Run the POLAR COORDINATES filter (Filter>Distort>Polar Coordinates) with
 the RECTANGULAR TO POLAR selection checked.  This filter mimics the
 distortion that occurs when a flat texture is applied to a sphere.  As
 such, you will see pinch point in the middle of the image, just as you
 would if you mapped the image onto a sphere.
 
 Paste the small feathered selection of your image over that pinch point.
 To reverse the effect, run POLAR COORDINATES again with the POLAR TO
 RECTANGULAR option selected.  By doing this you are essentially "unmapping"
 the sphere effect, wo when you apply this texture to a sphere it will not
 have the pinch point.
 
 Your image is now ready to seamlessly map onto a sphere.  Special thanks to
 John Knoll of ILM fame for writing Polar Coordinates and then explaining
 how to do this.