Sending Instant Messages

I've looked all over the www for an answer to this, but all I have found was an example on 4guys to send IM's. The problem is that they use Application variables. Is there a way to connect to existing IM services such as MSN and send IMs?What I want to do is send our CSRs an IM when their manager assigns a job to them through a management console I built.

I saw some stuff on Toast pop-ups with .NET on windows messenger service, but that's a little too deep for me. I would love to implement something like this, but I suspect that sending IM's through the Internet isn't going to be an option because of the spam implications. You can get server software like sharepoint to handle this type of stuff, but cost is a limitation.If there is an alternative solution, I would love to hear it. I am also open to .NET options as well.