You can look for soldiers at the Civil War Soldiers and Sailors System website:
http://www.itd.nps.gov/cwss/

The information isn't as detailed as what is in the Ohio roster, but it is a very useful site. Besides the names index (compiled from the index to the compiled service records), you can find unit histories, battle summaries, some prison rolls (currently Andersonville and Ft McHenry), and cemetery records for Poplar Grove.