If you're permitted to make use of a prefab codebase you can turn to CPAN. I found words. It is a part of the Bundle::PPT distribution (also see ppt-0.12).

The brief description for words is "find words which can be made from a string of letters."

The code for 'words' is all pure Perl, and having looked it over, it doesn't seem terribly complex. You might at least use it as a startingpoint.