File Attributes

I have 3 Linux servers and 2 Windows 2000 Servers. During each month the servers need to update files from one to another. This is done by a simple copy process. The files have grown so large that it takes quite awhile to accomplish. Is there anyway to have the Linux servers only copy changed files. The Windows files are no problem but I cannot find anywhere to copy only changed files from the Linux servers. Point me in the right direction