I believe it was in the Chicago Sun Times.

If Obama is the nominee you will hear more...

The long and short of it is: Obama paid 1/10th of what Resko paid for the lot next door.

So it appears that if the two parcels were of more or less equal value before they were sold, that there was some sort of agreement between the 3 parties that Resko was going to subsidize Obama's purchase. Ie. a bribe. Resko paid way more than his parcel was worth so that Obama could pay way less than his parcel was worth. One of those property deals that only politicians seem to get...Ie. a bribe.

By the way I made an error in my original post. Resko hasn't been convicted of anything yet. Jury selection in his corruption trial started yesterday. It will be 3 months or more before he is officially a convicted felon. the current Illinois governor has been named in the pre-trial paperwork as "Politician A". So this should be another interesting Illinois fiasco to watch unfold. The do things in their own way on that side of the Big Muddy.