Yes, Flash Player has sent text to the big two (JAWS and WindowEyez) since 2002 or so, and is also supporting an opensource screenreader effort:
http://blogs.adobe.com/accessibility/2009/08/adobe_supports_...
(I think Apple may have finally added an API which browser plugins can access for their text-to-speech, but I'm not sure how many people have moved over there yet.)
(that's not rhetorical; if anyone knows of one, I'd like to know)