From The New Republic's Spencer Ackerman's IRAQ'd blog:
To use the shorthand "six major parties" is deeply misleading. There are four political parties included here that can fairly be called "major": The Kurdistan Democratic Party; the Patriotic Union of Kurdistan; the Supreme Council for the Islamic Revolution in Iraq (SCIRI); and the Da'wa Party. The final two parties would be considered marginal were it not for the longtime patronage of the United States: Iyad Allawi's Iraqi National Accord and Ahmed Chalabi's Iraqi National Congress. (Yes, them again--apparently you can mislead the U.S. on intelligence about Iraq and then pass sensitive U.S. information to your longtime Iranian "liaison" and still not lose the support of the Pentagon and Vice President.)
As the Times notes, this is essentially calling the old Governing Council out of retirement to reprise their greatest hits--like "Hey! (Why Don't You Trust Me)" and the follow-up single, "Exiled (From Your Heart)." It's a curious arrangement. If the stated purpose is to curb Iranian influence, bringing Chalabi back into the mix is counterproductive.