Here are some links and commentary on the Day 2 arguments at the Supreme Court, concerning the individual mandate.
WSJ, 3/27/2012: "Conservative Justices Challenge Government Over Health Law"
NYT, 3/27/2012: "Hard Questions From Justices Over Insurance Mandate"
Fox News, 3/27/2012: "Health care law endures tough questioning from swing justice at Supreme Court showdown"
Multiple websites have copies of the audio and transcript for those who are interested.