PERL Mirror Script
Yes, I know that there are other tools out there, and I am especially aware of 'rsync', but there was a need for a PERL-based mirror tool. I wrote one that only copies the file if the size is different or the source timestamp is newer than the destination timestamp. It works extra-good if it is copying to/from the same filesystem or when the filesystems have the same time.
Download it as mirror.txt and you'll likely want to save it as mirror.pl. It requires the PERL module File::Copy. Open up mirror.pl and make sure that the $Source and $Dest parameters are set up.