tell application "Finder"
display dialog "Choose computer:" buttons ¬
{"Workstation_1", "Workstation_2"} default button 2
if the button returned of the result is "Workstation_1" then
set machine_chosen to "eppc://Workstation_1:password@192.168.1.45"
else
set machine_chosen to "eppc://Workstation_2:password@192.168.1.46"
end if
display dialog "" default answer "How are you doing?" buttons ¬
{"Cancel", "Send"} default button 2
copy the result as list to {text_returned, button_pressed}
end tell
tell application "Finder" of machine machine_chosen
activate
beep
display dialog text_returned buttons {"Cancel", "OK"} ¬
default button 2 giving up after 30
set the clipboard to the text_returned
end tell
To make this AppleScript work, activate Remote Apple Events in the Sharing preference pane on the machine you want to send a message to. Change the machine names, passwords, and IP's, save the script in the Scripts folder of your own machine, and send your message. The set the clipboard to the text_returned line I added to let the receiver use the text I send them, if they wish. They then paste the text anywhere they want.
Just to be secure: make sure your network security settings won't allow events from unknown IP numbers, and turn on the Firewall.

