The Federation of Genealogical Societies is holding its annual conference from 7 through 10 September 2011 at Springfield, Illinois. You can get all the info you need at their website.
Here is a notice we received recently in email:
"The Federation of Genealogical Societies invites you to the FGS/ISGS 2011 Conference for the Nation's Genealogists. Our local host, the Illinois State Genealogical Society, joins FGS in welcoming you to historic Springfield as we celebrate "Pathways to the Heartland."
Click here for their website, conference registration, and full conference booklet: http://fgs.org/2011conference/registration/