http://www.uvmapper.com/
UVMapper Pro only works with .obj files, so to get started, load the .x file for the required character into Milkshape, then export it as an .obj file.
Load the .obj file into UVMapper Pro then select Tools > Vertices > Weld
This glues all the polys together.
Now select Tools > Normals > Smooth, and accept the default smoothing angle.
Finally, select Tools > Materials and set the diffuse and ambient colours to white.
You can now work on your texture map in PSP or whatever, and whenever you copy to the clipboard (Ctrl+C) your texture will be loaded onto the mesh in UVMapper Pro so you can see how it looks.