Take your original in Photoshop, duplicate the layer. Open the high-pass filter dialog. Move the slider until you get maximum contrast. Set layer mode to overlay. Adjust opacity as needed. If that's not enough for you, open the USM (unsharp mask) dialog afterwards and raise the pixel threshold.
There are several ways of achieving this effect. Maxbloom mentioned one of the most common. A lot of people use the LucisArt plug in. http://www.lucisart.com/.
I however urge you first to research techniques in PS to achieve the same effect. Also, in my opinion people over use this effect far too often, but then again I over use plenty of techniques so who am I to say?