Currently the best one I've used is the OpenConvo thing...the actual listening-to-port program isn't a messenger plugin (but some kind of third-party port listener, listening to the two (open/close) special messages) but the DLL does receieve messages from the port listener and then display corresponding Messenger Plus! toasts...
![:)](images/smilies/msn_happy.gif)
Plus! API documentation itself doesn't provide the platform for you to do this
![:)](images/smilies/msn_happy.gif)