Unlike earlier editions of the building code, which stood on their own, the 8th edition of the Mass. Building Code "is comprised of the International Building Code 2009 (IBC) and a separate package with Massachusetts amendments to chapters of the IBC." You can't get both documents at one site. Users will need to go to the International Code at the International Code Council, and then read it in conjunction with the 8th edition Massachusetts amendments at the state's site.
The state advises: "User tip: First find a topic location in the IBC table of contents. Then come back to this screen, open the appropriate MA amendment chapter and scroll to the specific section to see if there are amendments that apply."
The 8th edition is effective concurrently with the 7th edition until February 6, 2011, when the 7th edition's effectiveness expires.