There are many collections of digital resources on the open web.  Here are a few that might be of use for your research project for this course:

Champaign County Cultural Memory Project (images of local life from the 1940s to the 1990s)

American Social History Online (search a large number of collections of digital images, texts, maps, oral histories, music and other resources from the 19th and 20th centuries) 

American Memory Project  (designed as a "visual record of American history," includes written and spoken word, sound recordings, still and moving images, photos, maps, and sheet music)

Illinois Harvest  (gateway to Illinois-themed or -produced material digitized by UIUC Library)

Digital Sanborn Maps (Illinois)  (plans of cities and towns created between 1867 and 1970 by the Sanborn Map Company as a tool for determining fire insurance risks)

Internet Archive  (digital library of more than 500,000 texts, including many publications relating to Illinois history, digitized from our collections by the Open Content Alliance)

Google Book Search (the other main digital library project)

Harvard Open Collections  (includes Immigration collection)