Here is the latest full crop illustration by the NeoCamera:-
http://www.neocamera.com/review_pentax_k7_sharpness.html
(Any of all possible settings can be freely selected)
Play with the different settings and find out the differences, yourself!
In short, the Sharpness, Fine Sharpness, Fine Sharpness 2 of the latest Pentax DSLRs (namely, the K-m, K-7 and K-x) are possibly just USM (UnSharp Mask) with different Radius (and certain appropriate Threshold) whilst the Strength can be user defined, i.e., the +/- 4 settings.
To understand more about USM for image sharpening, I recommend the following articles for reading:-
http://www.scantips.com/simple6.html
(Explained in a simpler way but still much detailed)
http://www.cambridgeincolour.com/tutorials/unsharp-mask.htm
(Explained in a more technical approach (just a little bit) for better understanding on the software manipulation done by the USM)