These were all done in Photoshop with the smudge tool (a few have backgrounds made with PS art history brush). Smudging is really pretty easy... just takes some practice.
To smudge paint in PS, here's what you do.
Before starting, you will want to adjust the tone and color of the image. If you don't want to work too hard, autolevels faded back a bit is usually helpful. For duller less contrasty photos, it's a good idea to use a fairly strong USM to pull out color and contrast...depends on the image. Setthe top slider to 400+ and adjust the middle slider farther and farther out till you get good contrast separation without extreme black areas. Go beyond "sharp" since that's not the goal here.
Working on a dupe, as usual, choose the smudge tool and the soft brush or Linda's smudge brush, and for hair/fur choose one of Sarsa's hair brushesor a brush with some "bite" to it, such as dry brush, spatter, stipple, rough round bristle, etc. (The brushes I prefer are shown in the attachment below.) If you want a smoother look, use charcoal or chalk, etc., or use more repeated strokes and vary brush size and opacity in your painting. You can mix brushes too, for different parts of the picture.
Photoshop's "dashed circle 2" is a good choice for swirling backgrounds, as well as doing the whole picture when a smaller brush is used--I did all of Opie in photo art challenge #001 with just this circle brush. And I used a larger one on Bubba's JT for a quick and deliberately messy result. Experiment with using different brushes, and if you get a good new effect, be sure to let us know!
Brush size will depend on the size and resolution of your image, so experiment a bit before deciding on a general size range that works well for you in that size, and make a note of these combinations of image size + brush size to help you get started on future pics.
Set brush opacity between 20-50% for skin and 75-85% for hair. Set the brush mode to normal or lighten or darken, depending on the area you are painting. Separating the lights and darks gives a less smeary effect in the end and sharper hairs, etc., though on large flat areas it tends to leave white or black specks, which can be touched up with the opposite setting or a bit of normal. Experiment with the three modes to see the differences yourself, then choose the one which gives the best effect on your image.
Do background first, then outer subject areas such as clothing, followed by the face in the case of a portrait. Use a narrow brush to define edges and shadows. Whether human or animal, you will want to do the hair last.
It's helpful, but not always necessary, to put the person or animal on a separate layer. The edges of your selection when removing subject from background don't need to be perfect on the hair areas since you'll smudge that out and over later... same for all edges to some degree.
For large areas with little detail, you can "scrub" the brush...this works great if you are using lighten and darken modes. If scrubbing in normal mode, lower opacity a bit to avoid over-smearing. Scrub in a back and forth motion, changing direction as the picture itself changes direction, following the main outlines of the pic.
Eyes: On people, use a small brush for eyes, of course, alternating between lighten and darken settings for different parts of eye. Put eyelashes on by drawing dark eyeliner with a tiny brush, then brush out in a curve from the dark line with tiny brush set to darken or normal mode. Use very high opacity, but never 100%... keep the lashes looking natural. You can use the smudge brush like this to add eyelashes on any photo touch up, not just when smudge painting a picture.
Save the hair areas for last. This is the fun part! Don't scrub on hair, but pull smoothly and quickly to follow the shape of the hair. Pull out and away to blend the hair over the background. Keep your undo button handy... some strokes will go astray! Switch darken or lighten mode to blend in washed out or overly dark areas, pulling from dark to light or vice versa.
After smudging the whole picture, adjust levels and color, then use a burn tool set to shadows on areas you want to accent more as "lines", such as grooves between hair smudges where contrast wasn't sufficient. A dodge tool set to "highlights" can be used as well to add sparkle and highlights and increasing contrast locally to define hair etc. Alternatively, you may paint in overlay mode with black to darken and white to add highlights.
For final tweaking, I recommend unsharp mask to bring out the texture of the strokes in hair etc, but I do the sharpening on a second layer, so I can erase away the parts I don't want to be so sharp, using a large low-medium opacity eraser. Some of the pics above that have sharper lines were done with USM and anisotropic diffuse. To learn more about this addition to smudging, see the tute called Smooth Portraits and Fine Edges.
Each picture is different. Sometimes you want a hard look, sometimes a soft look... basically sharpening is good for creating a harder look with more defined edges.
As a final step, you'll want to run a large fuzzy dodge tool set to highlights with low opacity over appropriate parts of the image to give it energy! To find these highlighted areas if they are hard to see, try adjustment>threshold and darken to heavy black to see the areas that remain white. Those are the dodging areas. Opposite, of course, to find any areas that need some burning.
Here's a tip on bringing out the strokes of your smudge:
viewtopic.php?p=89695#89695
_______________________________________________
I'm sure
I'm not the first person to think of painting with the smudge tool, but I stumbled on the 
idea working on a face over at RTP years ago, and Amanda Adams gave it the name "smudge painting" and we've called it that ever since.The pictures below are "before and after," showing how the smudge technique affected the photo.
I can't wait to try them out myself!
