Joel Oleson has written an article on some of the subjects we usually don’t have much information about, restrictions and recommendations on File Name, Length, Size and Invalid Characters in MOSS and WSS.
For MOSS and WSS sites planners this is always something to take into account as well as to prevent misuse form the client.
“Something that often comes up in deployments and migrations is what is allowed? What characters are supported. Rather than saying what’s supported, it’s a lot easier to say what is blocked and what is not allowed. ”
You can find this article here.