how to...

From My application, I want two or more pc to exchange
string (text)using the network

first something like broadcast a string
to all pc on the network

second to be able to receive the string send by
a pc andfrom who it was sent

In resume I want my application to 'speak' to
other pc on the network that have my application
running and only my application.

thank you for your time.
sylvain.