Understanding broadcast/multicast

I'm a little confused and hoping for some direction. I have a service (well, I will, anyway) that is connected to a COM port and justs waits until a message comes in - the message is an incoming 911 call - usually contains around 500 bytes - phone number, location, name info etc.

What I want to do is forward this message to "subscribed" clients (in a LAN). I'm thinking of creating a user control and add this to my app. Thinking of UDP - that way the service can just send the message and doesn't really care who picks it up.

Is multicasting the way to go? I've done some reading, but not really sure if I understand it. It would be nice if the service can just send a message without even having to worry about who is subscribed.

Any thoughts appreciated.

Mike

In case anyone is interested, here's a good link
http://www.vbip.com/books/1861007353...er_7353_01.asp