Go from to in PSPX. (The images are thumbnails; click for full size)
Easily translated to other versions of PSP. Translatable to PS and GIMP if you know the equivalent of tetxture preserving smooth.
Duplicate your base and set it to overlay 40%. Go to Adjust -> Blur -> Gaussian Blur, and set the radius to 2. My picture now looks like this:
Make a new layer and fill it with FFC99D, at Dodge 25%. My picture looks like this now:
Create another new layer and fill it with 0000FF. Set it to exclusion 34%. My picture is now like this:
Duplicate your base layer and smooth it out. Go to Adjust -> Add/Remove Noise -> Texture Preserving Smooth. Set the amount of corretion to 50. Set this layer to soft light 100%, and we're done! Pretty easy, huh? My final outcome looks like this: