file syncronization

I would like to know if anyone here knows how to syncronize files. Basically i need to know how to tell if a file has changed since i last downloaded it. What i want to do is syncronize two directories on two servers over ftp and need to only download what files have changed. Is there a way to tell by date or certain file atrribute? Thanks for all the help. Marc Ray marcray@visto.com marc@holographic.com ___________________________________________________________________________ Visit http://www.visto.com/info, your free web-based communications center. Visto.com. Life on the Dot.