The Madison-Jefferson County Public Library has a new section on its Web site (www.mjcpl.org) called "Historical Rescue Project"
Given the fire at the county courthouse, this is the best source of information on Jefferson County marriages from 1851 through 1965. The 1905 through 1965 records has the marriages on line, but also has downloadable files that show information from marriage applications, which usually listed parents of the couple. It is the most complete record of marriages available post-1850 and the first I am aware of that has the post 1900 marriages.
Also online are the Gans and Vail undertaker records, Fairmount Cemetery Internment records (from the cemetery records, not the tombstone transcriptions) and City of Madison death records from 1838 (which look to me like transcriptions of the Springdale Sexton's records) There is a Will section, but it appears to be only part of the wills in the 1800s, but includes more wills and probates in the second half of that century that are not included in the DAR transcriptions