An attempt to summary the Chicago Sun-Times article, "Barack Obama And His Slumlord Patron" (their title, not mine):

    Since the early 1990s, real estate developers Antoin "Tony'' Rezko and Daniel Mahru received a great deal of funds from the city of Chicago to develop low-income housing, about 30 apartment buildings.

    They didn't do a good job of maintaining any of them - leaving one without heat for five weeks in the middle of winter, for example.

    They used a small Chicago law firm , including a junior lawyer by the name of... Barack Hussein Obama.... to secure that government funding for about half of the buildings.

    In 1997, when the heat was off in those buildings, Rezko and Mahru managed to find money to donate to the political campaign fund of a young state legislator named... Barack Hussein Obama.

    Professonal and personal ties between Obama and Rezko were good friends for 17 years.

    Over the years, the buildings ran into a slew of problems - seventeen ended up in foreclosure, six are boarded up, twelve faced lawsuits filed by the city for a failure to heat the building and there are still millions of dollars' worth of unpaid loans.

    Rezko was charged last fall with demanding kickbacks on state business deals under Gov. Blagojevich.

    The previous Rezko problem for Obama was tied to his home purchase; Obama paid $300,000 less than the asking price for South Side mansion, while Rezko's wife paid the seller full price for the vacant lot next door. Then Obama bought part of that lot from Rezko's wife.