The Northampton Mayor’s office has just announced that the final settlement agreement to purchase the homes near the landfill has been made public and posted on the city website at this address:
http://www.northamptonma.gov/dpw/Landfill/
The link is called: “Final Settlement Agreement to purchase homes by landfill, May 2009”. You may also download this agreement here (PDF, 403KB) or view the pages below. 
See also:
Water Not Waste Seeks Signatures, Donations
Video: Special Meeting of the Board of Public Works and the City Council, 8/21/09; Landfill Ballot Question No. 2
Paradise City Forum: Landfill and Aquifer
Department of Public Works: Landfill Documents
Northampton Solid Waste Alternatives Google Group