A while ago I already posted a couple of snippets improving the quality of the existing PSSM shadows within the gamestudio templates.
Looking at that code again I found a couple of issues and things to improve.
I also plan to include point and spot lights at some point.

PSSM Improvements (so far):
- No flickering if the camera moves.
- Slightly tighter frustums resulting in slightly improved shadow resolution.
- Kinda hacky, but still a lot better biassing using depth derivatives.

The biggest still existing issue is the way the shadows are mixed with the scenes shading, which is just totally wrong, but this should be handled in custom shaders for the scene objects and is not really part of this.

You can get the code on github.

Here is an ugly screenshot of my testlevel (the worst way to present shadows is on untextured cubes...):