When I want to find something specific like this, I use the advanced search on Google and limit search results to one of my favorite bibliography sites: www.llrx.com. The search yielded a guide to federal and state election resources. Here's the link to the guide:
http://www.llrx.com/columns/roundup31.htm. Follow the link to Massachusetts resources by clicking on the state table.
Massachusetts
The Elections Division offers guides covering voter registration, absentee ballots, running for office, and more. The 2004 primary and election schedule is online, along with the calendar and candidates in special elections. Historic information includes ballot measures from 1919-2002 and 2002 election results. Take the Office of Campaign and Political Finance link to the search the database of financial reports filed by candidates and state ballot question committees. Legislators’ reports are also available broken down by district, and the office offers lists of registered candidates and committees and images of independent expenditure reports