There is an excellent article by Tami Osmer Glatz in the February 2012 edition of Family Tree Magazine called "It's Academic." Below is an excerpt:
You never quite know what you might find in your local college or university library. For example, the one at Marietta College, a small private college in southeast Ohio, has the original 1810 census for that part of the Buckeye State. It's the only complete 1810 census known to exist for any part of the state. Another gem: A 1798 tax list for Waterford Township in Washington County, Ohio. Not only did this particular tax-man list freemen, lodgers, servants, land and other taxable possessions, but if you flip to the back of the booklet, you'll see he included the names of every person - even women and children - in each household.
In the article, Ms. Glatz includes links to many on-line resources, such as:
Making of America Collection: cdl.library.cornell.edu/moa
Ohio's Heritage Northeast, www.ohiosheritagenortheast.org
West Virginia University's library, www.libraries.wvu.edu/wvcollection/genealogy.htm
University of Iowa Digital Library, digital.lib.uiowa.edu
I have never used a university or college library for genealogy research, but after reading Ms. Glatz's article, realize I may have overlooked an excellent research resource.
Ms. Glatz also has a very information blog called Relatively Curious About Genealogy, relativelycurious.blogspot.com.