network messaging

i am writing a server reboot utility that will reboot a windows server at specified times or remotely from another machine. I have the code to reboot the machine but want it to despatch a message to all machines on the network first. Is there a way to use winpopup to do this, can i call it with a string to depatch?

system("net send * hello");


net send [IP] [message string] would be the syntax. that will send a message (like a message box popup) to all the computers on the same workgroup