Various articles out on the web seem to be pointing to an introduction, probably a large-screen Kindle, at a press conference on Wednesday:
New York Times:
http://www.nytimes.com/2009/05/04/te...ref=technology
(who's apparently part of the introduction)
http://mediamemo.allthingsd.com/2009...mod=ATD_sphere
gives some more details. If it's at Pace University, then it might be the college reader, 9.7" screen, that's been rumored for some time. E-ink was supposed to begin shipping those in April.