Use File::Find to recurse through subdirectories, the module docs provide very clear examples on its simple usage. You will have access to each file in the directory, match on .html or .htm to get only the files you want.
To get to the title tag you might be able to use HTML::Parser
enjoy!
Update : bah bikenomad is clearly psychic as he posted exactly the same suggestions.... we are actually the same person, i'm Dr. Jekyll