I think that it should be possible to determine if a process with that name is already running, although I've never tried doing that in code before. If you're running on Windows, you might want to check out http://roth.net/ to see if they have a Win32 module that help you out.

As for doing this in *nix, don't know. If there are no Perl modules that do this, there may be shell/system commands that can help. However, I know just enough to be dangerous in the *nix environment. That means I know how to run the rm command and can get into vi to modify files.