You can view the muster rolls by company at http://civilwar.ilgenweb.net/ There are also regimental histories on this site. Or you can view by regiment and company by typing in the search boxes on the IL Archives website at http://www.sos.state.il.us/departments/archives/databases.html

On the genweb site (first listing) be sure to go to the scrapbook link on the main page, as you will sometimes find other information there.

Hope this helps.
Ann