According to ESPN, Congress is requesting a hearing with Roger Clemens, Andy Pettitte, and Brian McNamee. The hearing is to be held January 16th. And David Marin, a member of the committee has made it clear what Congress is looking for.
ESPN asked committee member David Marin if the hearings were meant to gets answers from Clemens and Pettitte while they're under oath. Marin responded, "that's a question goes without saying. Under oath is under oath."
If Congress then suspects Pettitte or Clemens of lying under oath, they would likely be investigated for perjury, just like Barry Bonds. Perjury is a felony of the third degree, punishable by jail time. For those who were upset over the speculative nature of the Mitchell Report, you may get some irrefutable answers soon.