Send Message on selected System IP Address.

Question

Hi All,
I want to develop an application in which it will show list of IP address of all working System in LAN and when i select any IP address from list and want to show message box on selected IP address's System then it will show message box.

I am able to get all IP Address of all working system. but not able to send message on selected IP address's System.

So my question is that, how i send message at selected IP Address system?
I don't know much about Network and Socket Programming.

Please guide me what i need to do for this task and what is the best way to achieve them.
If you all have any reference book then please revert me back name of the book.


Regards
Dharmchand Dhingra