The WSJ says there was no plea agreement:
Madoff Expected to Plead Guilty in Massive Fraud
Mr. Madoff is expected to plead guilty to the charges on Thursday. If found guilty of all counts, Mr. Madoff, who has been free on bail since his arrest on Dec. 11, faces a maximum of 150 years in prison. Legal experts expect the actual sentence to be much lower but would still be an effective life sentence for the 70-year-old.
The charges were filed in what is called a criminal information, a document that details the crimes prosecutors say he committed. The document was filed by prosecutors in lieu of a grand jury indictment, which Mr. Madoff waived.
Lev Dassin, acting U.S. attorney for the Southern District of New York, said in a statement that the investigation is continuing and that “the filing of these charges does not end the matter.” As previously reported by the Wall Street Journal, prosecutors said there was no plea agreement with Mr. Madoff in which they might recommend that he receive leniency in sentencing.
The article also says,
By pleading guilty to the counts, Mr. Madoff would also face millions of dollars in possible criminal fines.
People entrusted Madoff with millions of dollars. That money had to go somewhere. The question is finding it.