You'll be a) wanting File::Find and b) actually looking for an answer before asking this all too common question. But if it's desperation you've come to here's some code -

use File::Find;

find(\&wanted, '/usr/local/src');

sub wanted {
    open(FL, $File::Find::name);
    # process stuff here #
    close(FL);
}
[download]

HTH

broquaint