Recursively fetch directory via FTP using WGET

wget --user=[user] --password=[pass] -r ftp://ftp.somesite.com/dirA/dirB/*

Just add the "-N" option to wget to ignore files older than what you have locally. You could also add the "-nc" to completely skip a file if it already exists, even if the one on FTP is newer.
http://superuser.com/questions/58300/latest-file-from-ftp-server-using-wget-or-some-other-way