It looks like the post-production includes some sort of tonal compression techniques aswell as split-toning and maybe some blur.
If you want to emulate this kind of look you can start with some basic curve manipulations in Photoshop. Tonal Compression works by clipping of shadows or highlights. You can achieve this by using the luminosity (RGB) channel within curves and making the curve 'less steep' (eg. taking the shadow point from input 0/output 0 to input 0 / output 18). That was probably done to Example 2 and 3, as you can see in the lack of really dark colors. Example 1 has been treated with a reverse treatment by clipping of the highlights making all the lighter colors grayish instead of full white, you can achieve this by taking the higlight point in curves (input 255 / output 255) and change it to eg. input 255 / output 214.
Split-Toning works in similar ways. Example 2 has probably been treated with the popular blue/yellow split-toning. It is achieved by manipulating the curves for the individual colors (RGB) in this case the blue channel. Switch to blue and pull the curve up in its left hand side (shadows), your dark colors should get a blue tint. Push down the curve in its right hand side (highlights), your lighter colors should get a yellow tint. You can do the same with the red and green curves to achieve different results.
You can look around the internet for different 'curve recipes', some artist share them freely. Look for example here: http://www.flickr.com/photos/rowenar/4929839059/ -- The link also shows a picture what I have been trying to explain so it should become more clear (for GIMP not PS, but it works the same way).
There are many more ways of achieving a split toning look. You can search for 'Gradient Mapping' or using solid color overlays with different blend modes (try for example a solid light blue color overlay in exclusion blend mode with an opacity of around 30, change the color to get a feeling for different looks)
For final touch of softness you can consider actually slightly blurring the picture using the gaussian blur or lens blur Filters. Apply some grain afterwards to counter the relative visible loss of sharpness.
You need to combine all these techniques in a skilled way to achieve a look like that -- or look for PS actions of which there are plenty.