contains a large digital archive of artifacts related to the American Bottom region, defined as the area south of the confluence of the Missouri, Mississippi and Illinois rivers. This includes portions of St. Clair, Randolph, Madison, and Monroe Counties in Illinois. Most of the information on the site appears to be centered on the Cahokia Mounds, and East St. Louis.
The site has moved to a new location on the University of Illinois at Urbana-Champaign's servers, and while they still have an interesting archive, it appears they have removed the East St. Louis City Directories.
Never fear, Illinois Harvest, a product of the UIUC library, has them.
Illinois Harvest has a large digital book collection for download, including over 400 entries under the subject header of County and Local Histories, another 400 under Church and Congregational History in Illinois, and 125 under Genealogy Resources.
The latter includes the 1813 and 1818 Pension lists, listing everyone in the US receiving a military pension in the given year. As well as a couple dozen Chicago "Blue Books" and social registers.