The £1million prize fund has been provided by NESTA - the National Endowment for Science, Technology and the Arts (an NDPB of the Department for Innovation, Universities and Skills). They have an open invitation to a reception from 5pm on 11 September 2008. See http://biggreenchallengefinalists.eventbrite.com/ to register.
The list and details of the finalists can be found at http://www.biggreenchallenge.org.uk/top-21-competitors/