Are you referring to sending a message from one user to another, both logged into the same machine, on the console? If so, use the `write` command. It does exactly that, and there's another thread around here somewhere where I showed an example of how to do it; if you cannot find it, or can't get it to work, or if this is totally not what you are wanting, I'll (or someone) will try to help more, just clarify if necessary (like maybe you wish to have the system log(s) from the server appear directly onto a console screen on a remote machine? The word "messages" is a bit misleading here -- it implies the /var/log/messages file as you mentioned, but might also mean user-user messages. I'd think it'd not be enjoyable to log into a server, and then the server starts filling your console with messages!)
So, anyhow, please clarify a little bit which it is you wish to do.