From the Fitzgerald statement:

On November 12, Blagojevich spoke with SEIU Official who was in Washington. This conversation occurred about a week after Blagojevich had met with SEIU Official to discuss the Senate seat, with the understanding that the union official was an emissary to discuss Senate Candidate 1's interest in the Senate seat. During the November 12 conversation, Blagojevich allegedly explained the non-profit organization idea to SEIU Official and said that it could help Senate Candidate 1. The union official agreed to "put that flag up and see where it goes," although the official also had said he wasn't certain if Senate Candidate 1 wanted the official to keep pushing her candidacy. Senate Candidate 1 eventually removed herself from consideration for the open seat. (itals ours)

Both Valerie Jarrett, a friend and adviser to Barack Obama, and Tammy Duckworth, an Iraq vet who runs the Illinois Veteran Affairs Department, have been mentioned as candidates for the seat.

There appears to be no allegation of wrongdoing by Senate Candidate 1.

Late update: The charges themselves say:

By this time, media reports indicated that Senate Candidate 1, an advisor to the President-elect, was interested in the Senate seat if it became vacant, and was likely to be supported by the President-elect.