I have several Windows clients that I want to replicate a single directory on to Linux server at a remote location. I was planning on using rsync with cygwin to do this. The problem is that I know that rsync can push data that exist on the client machines (windows) to the server with no problem, but can it pull data from the server as well? I don't want to have to have the server run a cron job to push the data to the clients, I want the clients to run rsync as part of a scheduled task and the just synchronize a particular directory with the Linux server. If a file exists on the Linux server that the client does not have, it will retrieve it too the clients. It this possible with rsync or should I be looking at something like unison.

Yes, rsync can do this. You can use rsyncd (the rsync daemon) on the server, or the --rsh="ssh" option to connect to the server via ssh.

I would have to run two seperate commands though correct? One to set up the push from the client to the linux server and the other to have the linux server push to the client?

Two commands, yes, but the rsyncs can be initiated by the clients (rsync is bidirectional). For example:

# Copy from client to server over ssh
rsync -av --progress --partial --rsh="ssh" somefile someuser@someserver:somedir/

# Copy from server to client, by the client
rsync -av --progress --partial --rsh="ssh" someuser@someserver:somedir/somefile /somedir/

The order of the parameters determines the direction (local->remote or remote->local).