Using PSP8 but probably transferable.
1. Crop your base. I sharpen AFTER I've done all my coloring, but you can sharpen now if you'd like.
2. Duplicate your base and set it to screen - I kept mine at 100% but this can vary dependig on your image.
3. Create a new layer and fill with #9CD9FF. Set to burn at 100%.
4. Create a new layer and fill with #CAAD98. Set to soft light at 100%.
5. Create a new layer and fill with #000226. Set to exclusion between 100% - 70% depending on your image.
6. Merge all layers.
7. Duplicate your base.
8. With your duplicated layer selected, go to Adjust > Hue & Saturation > Hue/Saturation/Lightness. Put your saturation to 40. (Option al - some pictures look good if you set this to soft light)
9. Merge all layers. Sharpen, if you haven't done so yet.
10. Duplicate your base layer. Using your move tool, move the duplicated base down so you can see Mischa's face twice.
11. Create a new layer. Fill it with black (or any color you wish) and leave it at normal. I usually lower the opacity to about 70% just so I can see what I'm doing and then bring it back up to 100% when I'm done.
12. Use your move tool to move the black layer so it only covers the first part of the icon. Set your selection tool to "rounded rectangle" and use it to draw a rectangle in the black portion, like this
13. Press "delete" and bring the opacity of the black up to 100%.
14. Now duplicate that layer. Go to Image > Flip to flip it around.
15. Voila! Now add brushes/text/whatever you like.
I hope this tut was easy to follow - if you have any questions don't hesitate to ask & I'll try my best to answer them.
Join illusion_iicons for tons of celebrity & stock icons/headers/etc. I'm currently working on a huge batch of icons like the one above.