G8 Summit Resource
Well, this find seemed topical. There is a G8 research group at the Munk Centre for International Studies at the University of Toronto. The group maintains a very useful website: http://www.g8.utoronto.ca/ which provides access to a large chunk of the group’s analysis and reports. Monographs published by commercial publishers are not available online.
The site also links to available “Delegations; declaration and communiqués; other official releases; documents released by national delegations at summits; available transcripts of summit news conferences” for G8 & G7 summits dating back to the 1975 Summit in Rambouillet.