find . -type d -exec chmod 0755 {} \;
find . -type f -exec chmod 0644 {} \;

##</code><code>##

#!/usr/bin/perl -w
use strict;
use File::Find;                                                                               

find(
  { wanted => sub{ chmod((-f)?0644:0755,$_) if -d||-f } 
  }, defined $ARGV[0] ? $ARGV[0] : '.'
);