There are indeed many ways. The big picture is this: you can choose to mount the remote volume, then just move or copy the file as you would copy it to another disk, using cp, mv, whatever. This can be done with nfs, sshfs, samba...
You can also choose to use a server-client model. In this case, you need to run a server in one of your machines, and launch the client in the other machine to literally upload your file to the server. This can be done usually with ssh (scp), ftp, rsync, and many other ways.
Both ways have advantages I guess, and often the line is thin. For example, if you have an ssh server running in your central machine, you can upload files to it by using either the scp file transfer tool, or by mounting the remote volume with sshfs and the using cp or mv to put the files inside the mounted share.
Last edited by i92guboj; 11-23-2009 at 07:13 PM.