Basic Coloring Tutorial...
I just thought I'd write a basic coloring tutorial without any levels, curves or other adjustment layers. A great & helpful tutorials for newbies as well. Anyhow, this was tested in PS CS and PSP 7 and I'm sure its transferrable to every other graphic program. Here it is;
Go from
to 
Okay, so here's the image I chose [Hilary Duff].

Then, crop or paste the image onto a 100 x 100 graphic. I got:

Then, UNSHARP MASK (Filter >> Sharpen >> Unsharp Mask) the image, and then after that, SHARPEN (Filter >> Sharpen >> Sharpen) the image. Here's what I came up with:

After you're done with that, duplicate the layer, and set it to Screen 60%. You should get something like:

Now for the colour layers. Fill with #272843 and set it to Exclusion 100% [like all tutorials. Haha.] Should look like this:

(I know it looks pathetic. Will get better.)
Another colour layer. Fill with #C0FFFF and set it to Color Burn 100%, and this is how the layer affected the icon:

Now, for the most important step. Fill with #C0C0C0 and set it to Color Burn 100%. Now it looks quite different. Here's what mine looked like:

Almost done! Now, duplicate the layer below the screen layer [the base] and set it to Soft Light, and bring it all the way to the top (above the greyish color burn layer). Now, the final icon should looke like:

We're done! Hehe. I hope you liked my..ehm..second tutorial. Much easier to understand compared to my first. Show me your results ;) also, try playing with the opacities to fit your image.
Go from
to 
Okay, so here's the image I chose [Hilary Duff].

Then, crop or paste the image onto a 100 x 100 graphic. I got:

Then, UNSHARP MASK (Filter >> Sharpen >> Unsharp Mask) the image, and then after that, SHARPEN (Filter >> Sharpen >> Sharpen) the image. Here's what I came up with:

After you're done with that, duplicate the layer, and set it to Screen 60%. You should get something like:

Now for the colour layers. Fill with #272843 and set it to Exclusion 100% [like all tutorials. Haha.] Should look like this:

(I know it looks pathetic. Will get better.)
Another colour layer. Fill with #C0FFFF and set it to Color Burn 100%, and this is how the layer affected the icon:

Now, for the most important step. Fill with #C0C0C0 and set it to Color Burn 100%. Now it looks quite different. Here's what mine looked like:

Almost done! Now, duplicate the layer below the screen layer [the base] and set it to Soft Light, and bring it all the way to the top (above the greyish color burn layer). Now, the final icon should looke like:

We're done! Hehe. I hope you liked my..ehm..second tutorial. Much easier to understand compared to my first. Show me your results ;) also, try playing with the opacities to fit your image.