You're probably looking for symlink, but if I were faced with this situation I would probably work on standardizing everything on lower-case. If your files are including other files using a mixed case, change it to lower-case, and then run through all of your files and change them all to lower-case. Your problem should then be solved without having to worry about building symlinks or other such manipulations.

Short of doing that, I would probably modify the files themselves to point to the correct name. I would view building a bunch of symlinks as a last resort.