After a very quiet year in 2005, the 2006 season was very active with major outbreaks in March and April. The National Oceanic and Atmospheric Administration (NOAA) Storm Prediction Center (SPC) does a nice job of documenting the preliminary reports of these events. Individual National Weather Service (NWS) offices often provide their own detailed reports as well.
Update (December 11, 2006): According to Chris Miller (NWS Lincoln), there have been reports of 124 tornadoes in Illinois so far in 2006. The number of reports in October and November is still being confirmed and December is not over yet. Even so, this exceeds the previous record of 120 set in 2003. Of the 124 reports 73 were rated as F0, the weakest category of tornado. Thanks to better radar and spotter networks and better public awareness, we now do a better job of finding these weaker tornadoes. As a result, the number of reports has climbed in recent years - due to better accounting, not climate change.