AppleScript & MSN Messenger

I am new to using AppleScript and I am trying to ultimately create a Growl notification for any incoming messages from MSN Messenger. I know you can use AppleScript to create the Growl notification but I am not sure how to code it so it will watch for any incoming messages.

I know that Growl itself is currently incompatible with MSN Messenger. However, can AppleScript access it?

Any help or guidance is greatly appreciated. Thank you.