Dear All

i want to design a software in which i play a role of server and all users in my office will be a clients. whenever IT department want to send any message to all i will write in server app and msg will appear on everyone's screen and when they click accept then i will receive confirmation email or message from that user. any idea

The idea you already have. What do you need help with?

I need any code or any open source code or website . I have idea but how to do that I want to knw

So you want us to find the code for you? Or do you want suggestions for websites which will teach you to code? If the former then you can use Google like anyone else. Ditto for the latter.

no guys . look i know in vb6 we do it using winsock but now i can do that in vb.net for that i need any example

You still can use sockets with VB.NET. Or you can use WCF Services, IIS Hosted Web Sites or Web Pages.
There's lots of ways of making a client server app with .NET;
You could even write files from one place to another, why not? What doesn't kill, only makes you fat.