Take photo with a pair of sunglasses. I provided a demo photo.

Import the photo you want to map on the sunglass. Make it a smart object so distortion isn't a factor. Resize it so all important elements are contained in the lens.

 

Go to Edit>Transform>Warp. You want to expand the middle box of the photo by bending out the wireframe.

 

Now use the magic wand to select the lens. You want to blend the glasses layer. Go to Filter>Blur>Blur More.

 

 

 

You might want to do this a few times. Now select the reflection photo layer and click the vector mask button on the bottom of the layer panel. Set the reflected photo to multiply. Do the same for the other lens.

 

Duplicate both reflected layers. Change the blending mode to lighten at 3% opacity.

If you want to tint the lenses, create a new layer select both lens and color it to any color. Set the blending mode to overlay.

 

Final Result

 

Discuss the Adobe Photoshop tutorials on the forums. You can find the photoshop files to download there too.