Rad,
 
Here is a product that Glenn uses and really likes.
I'd read the pages of the first link and then get the download
 
Warning! Unison Home Page for download is VERY SLOW
 
 

Unison File Synchronizer
http://web.mit.edu/pgbovine/www/unison_guide.htm


Unison Home Page
http://www.cis.upenn.edu/~bcpierce/unison