GovTrack.us, Senate.gov, and Ballotpedia.org are websites where you can find information regarding the current senators for Illinois. As of 2015, the U.S. senators from the state of Illinois are Democrat Richard Durbin and Republican Mark Kirk.
Govtrack.us displays information on the current senators and their political affiliations, senior and junior senator status, when they took office, and the next election year. Ballotpedia.org offers additional information on all the previous U.S. senators from the state of Illinois and the years they served. Senate.gov allows you to search for U.S. senators by state and class and from a list of all 100 current senators.