To send a message to another system

How to send a message to another unix terminal along with the date specified

(somehow double posted.....)

echo test `date` | wall

or perhaps something similar with "write"

i need to send messages to three systems of the same network.

You definately require to run some TCP/IP server on those system. You need not write any such server. You can use a marvolus tool named "NetCat (nc)". You can create a Shell Script and invoke that from "inet".
Other approach could be invoke such script from "r" (rsh, rexec) utilities, that may open some security threats.