Msn Instant Messenger and others

Is there such a way that it's possible to enable voice speaking when someone sends you a message. So say that if your not looking at the screen at the moment the person sends the message you could hear the computerized person that comes on apple read it out for you.

Also when it comes to Safari is their possibly a way I can make Speak abutton in the Bookmark Bar like the Print button to automatically begin reading the page without having to outline and then hit safari services etc.